gnu: Use gexps for gcc-boot0 and related packages.use-gexps-in-gcc-boot0

There are currently problems with native or cross building for i586-gnu, and
one factor mixed up with this is that some of the gcc packages use sexp's for
the phases, and thus introducing gexp's has caused problems.

As part of the going in circles with this, this commit switches gcc-boot0 to
use gexp's in it's arguments, and then also modifies libstdc++-boot0,
cross-gcc-wrapper, gcc-final and make-libstdc++ to handle this change.

If done correctly, this change shouldn't affect any derivations.

* gnu/packages/commencement.scm (libstdc++-boot0, gcc-boot0,
gcc-final)[arguments]: Use gexps.
(cross-gcc-wrapper): Use gexps in the generated package.
* gnu/packages/gcc.scm (make-libstdc++): Use gexps in the generated package.

2 files changed, 245 insertions, 241 deletions

diff --git a/gnu/packages/commencement.scm b/gnu/packages/commencement.scm
index fc1c508b38..5e47b272e4 100644
--- a/gnu/packages/commencement.scm
+++ b/gnu/packages/commencement.scm
@@ -2259,13 +2259,13 @@ exec " gcc "/bin/" program
              ((or "i686-linux" "x86_64-linux")
               (substitute-keyword-arguments (package-arguments lib)
                 ((#:phases phases)
-                 `(modify-phases ,phases
-                    (add-after 'unpack 'workaround-wrapper-bug
-                      ;; XXX: The crude gcc-cross-wrapper causes "g++ -v" to
-                      ;; fail, which in turn confuses the configure script.
-                      (lambda _
-                        (substitute* "libstdc++-v3/configure"
-                          (("g\\+\\+ -v") "true"))))))))
+                 #~(modify-phases #$phases
+                     (add-after 'unpack 'workaround-wrapper-bug
+                       ;; XXX: The crude gcc-cross-wrapper causes "g++ -v" to
+                       ;; fail, which in turn confuses the configure script.
+                       (lambda _
+                         (substitute* "libstdc++-v3/configure"
+                           (("g\\+\\+ -v") "true"))))))))
              (_ (package-arguments lib)))
 
          ;; Explicitly add #:modules so MAKE-LIBSTDC++ can be changed
@@ -2338,81 +2338,82 @@ exec " gcc "/bin/" program
              (system* #$(file-append coreutils-boot0 "/bin/rm") "-rf"
                       "gcc/testsuite/go.test/test/fixedbugs/issue27836.dir"))))))
     (arguments
-     `(#:guile ,%bootstrap-guile
-       #:implicit-inputs? #f
-       #:modules ((guix build gnu-build-system)
+     (cons*
+      #:guile %bootstrap-guile
+      #:implicit-inputs? #f
+      #:modules '((guix build gnu-build-system)
                   (guix build utils)
                   (ice-9 regex)
                   (srfi srfi-1)
                   (srfi srfi-26))
-       ,@(substitute-keyword-arguments (package-arguments gcc)
-           ((#:configure-flags flags)
-            `(append (list ,(string-append "--target=" (boot-triplet))
-
-                           ;; No libc yet.
-                           "--without-headers"
-
-                           ;; Disable features not needed at this stage.
-                           "--disable-shared"
-                           "--enable-languages=c,c++"
-
-                           ;; libstdc++ cannot be built at this stage
-                           ;; ("Link tests are not allowed after
-                           ;; GCC_NO_EXECUTABLES.").
-                           "--disable-libstdc++-v3"
-
-                           "--disable-threads"
-                           "--disable-libmudflap"
-                           "--disable-libatomic"
-                           "--disable-libsanitizer"
-                           "--disable-libitm"
-                           "--disable-libgomp"
-                           "--disable-libmpx"
-                           "--disable-libcilkrts"
-                           "--disable-libvtv"
-                           "--disable-libssp"
-                           "--disable-libquadmath"
-                           "--disable-decimal-float")
-                     (remove (cut string-match
-                               "--(with-system-zlib|enable-languages.*)" <>)
-                             ,flags)))
-           ((#:make-flags flags)
-            `(let* ((libc        (assoc-ref %build-inputs "libc"))
-                    (libc-native (or (assoc-ref %build-inputs "libc-native")
-                                     libc)))
-               `(,(string-append "LDFLAGS="
-                                 "-Wl,-rpath=" libc-native "/lib "
-                                 "-Wl,-dynamic-linker "
-                                 "-Wl," libc-native ,(glibc-dynamic-linker
-                                                      (match (%current-system)
-                                                        ("x86_64-linux" "i686-linux")
-                                                        (_ (%current-system))))))))
-           ((#:phases phases)
-            `(modify-phases ,phases
-               (add-after 'unpack 'unpack-gmp&co
-                 (lambda* (#:key inputs #:allow-other-keys)
-                   (let ((gmp  (assoc-ref %build-inputs "gmp-source"))
-                         (mpfr (assoc-ref %build-inputs "mpfr-source"))
-                         (mpc  (assoc-ref %build-inputs "mpc-source")))
-
-                     ;; To reduce the set of pre-built bootstrap inputs, build
-                     ;; GMP & co. from GCC.
-                     (for-each (lambda (source)
-                                 (invoke "tar" "xvf" source))
-                               (list gmp mpfr mpc))
-
-                     ;; Create symlinks like `gmp' -> `gmp-x.y.z'.
-                     ,@(map (lambda (lib)
-                              ;; Drop trailing letters, as gmp-6.0.0a unpacks
-                              ;; into gmp-6.0.0.
-                              `(symlink ,(string-trim-right
-                                          (package-full-name lib "-")
-                                          char-set:letter)
-                                        ,(package-name lib)))
-                            (list gmp-6.0 mpfr mpc)))))
-               ,(match (%current-system)
-                  ((or "i686-linux" "x86_64-linux")
-                   '(add-before 'configure 'fix-libcc1
+      (substitute-keyword-arguments (package-arguments gcc)
+        ((#:configure-flags flags)
+         #~(append (list #$(string-append "--target=" (boot-triplet))
+
+                         ;; No libc yet.
+                         "--without-headers"
+
+                         ;; Disable features not needed at this stage.
+                         "--disable-shared"
+                         "--enable-languages=c,c++"
+
+                         ;; libstdc++ cannot be built at this stage
+                         ;; ("Link tests are not allowed after
+                         ;; GCC_NO_EXECUTABLES.").
+                         "--disable-libstdc++-v3"
+
+                         "--disable-threads"
+                         "--disable-libmudflap"
+                         "--disable-libatomic"
+                         "--disable-libsanitizer"
+                         "--disable-libitm"
+                         "--disable-libgomp"
+                         "--disable-libmpx"
+                         "--disable-libcilkrts"
+                         "--disable-libvtv"
+                         "--disable-libssp"
+                         "--disable-libquadmath"
+                         "--disable-decimal-float")
+                   (remove (cut string-match
+                                "--(with-system-zlib|enable-languages.*)" <>)
+                           #$flags)))
+        ((#:make-flags flags)
+         `(let* ((libc        (assoc-ref %build-inputs "libc"))
+                 (libc-native (or (assoc-ref %build-inputs "libc-native")
+                                  libc)))
+            `(,(string-append "LDFLAGS="
+                              "-Wl,-rpath=" libc-native "/lib "
+                              "-Wl,-dynamic-linker "
+                              "-Wl," libc-native ,(glibc-dynamic-linker
+                                                   (match (%current-system)
+                                                     ("x86_64-linux" "i686-linux")
+                                                     (_ (%current-system))))))))
+        ((#:phases phases)
+         #~(modify-phases #$phases
+             (add-after 'unpack 'unpack-gmp&co
+               (lambda* (#:key inputs #:allow-other-keys)
+                 (let ((gmp  (assoc-ref %build-inputs "gmp-source"))
+                       (mpfr (assoc-ref %build-inputs "mpfr-source"))
+                       (mpc  (assoc-ref %build-inputs "mpc-source")))
+
+                   ;; To reduce the set of pre-built bootstrap inputs, build
+                   ;; GMP & co. from GCC.
+                   (for-each (lambda (source)
+                               (invoke "tar" "xvf" source))
+                             (list gmp mpfr mpc))
+
+                   ;; Create symlinks like `gmp' -> `gmp-x.y.z'.
+                   #$@(map (lambda (lib)
+                             ;; Drop trailing letters, as gmp-6.0.0a unpacks
+                             ;; into gmp-6.0.0.
+                             #~(symlink #$(string-trim-right
+                                           (package-full-name lib "-")
+                                           char-set:letter)
+                                        #$(package-name lib)))
+                           (list gmp-6.0 mpfr mpc)))))
+             #$(match (%current-system)
+                 ((or "i686-linux" "x86_64-linux")
+                  #~(add-before 'configure 'fix-libcc1
                       (lambda* (#:key inputs #:allow-other-keys)
                         ;; libcc1.so NEEDs libgcc_s.so, so provide one here
                         ;; to placate the 'validate-runpath' phase.
@@ -2423,18 +2424,18 @@ exec " gcc "/bin/" program
                         ;; XXX: "g++ -v" is broken (see also libstdc++ above).
                         (substitute* "libcc1/configure"
                           (("g\\+\\+ -v") "true")))))
-                  (_ '(add-before 'configure 'return-true
+                 (_ #~(add-before 'configure 'return-true
                         (lambda _ #t))))
-               (add-after 'install 'symlink-libgcc_eh
-                 (lambda* (#:key outputs #:allow-other-keys)
-                   (let ((out (assoc-ref outputs "lib")))
-                     ;; Glibc wants to link against libgcc_eh, so provide
-                     ;; it.
-                     (with-directory-excursion
-                         (string-append out "/lib/gcc/"
-                                        ,(boot-triplet)
-                                        "/" ,(package-version gcc))
-                       (symlink "libgcc.a" "libgcc_eh.a"))))))))))
+             (add-after 'install 'symlink-libgcc_eh
+               (lambda* (#:key outputs #:allow-other-keys)
+                 (let ((out (assoc-ref outputs "lib")))
+                   ;; Glibc wants to link against libgcc_eh, so provide
+                   ;; it.
+                   (with-directory-excursion
+                       (string-append out "/lib/gcc/"
+                                      #$(boot-triplet)
+                                      "/" #$(package-version gcc))
+                     (symlink "libgcc.a" "libgcc_eh.a"))))))))))
 
     (inputs `(("gmp-source" ,(bootstrap-origin (package-source gmp-6.0)))
               ("mpfr-source" ,(bootstrap-origin (package-source mpfr)))
@@ -2888,41 +2889,42 @@ that makes it available under the native tool names."
     (build-system trivial-build-system)
     (outputs '("out"))
     (arguments
-     `(#:guile ,%bootstrap-guile
-       #:modules ((guix build utils))
-       #:builder (begin
-                   (use-modules (guix build utils))
-
-                   (let* ((binutils (assoc-ref %build-inputs "binutils"))
-                          (gcc      (assoc-ref %build-inputs "gcc"))
-                          (libc     (assoc-ref %build-inputs "libc"))
-                          (bash     (assoc-ref %build-inputs "bash"))
-                          (out      (assoc-ref %outputs "out"))
-                          (bindir   (string-append out "/bin"))
-                          (triplet  ,(boot-triplet)))
-                     (define (wrap-program program)
-                       ;; GCC-BOOT0 is a libc-less cross-compiler, so it
-                       ;; needs to be told where to find the crt files and
-                       ;; the dynamic linker.
-                       (call-with-output-file program
-                         (lambda (p)
-                           (format p "#!~a/bin/bash
+     (list
+      #:guile %bootstrap-guile
+      #:modules '((guix build utils))
+      #:builder #~(begin
+                    (use-modules (guix build utils))
+
+                    (let* ((binutils (assoc-ref %build-inputs "binutils"))
+                           (gcc      (assoc-ref %build-inputs "gcc"))
+                           (libc     (assoc-ref %build-inputs "libc"))
+                           (bash     (assoc-ref %build-inputs "bash"))
+                           (out      (assoc-ref %outputs "out"))
+                           (bindir   (string-append out "/bin"))
+                           (triplet  #$(boot-triplet)))
+                      (define (wrap-program program)
+                        ;; GCC-BOOT0 is a libc-less cross-compiler, so it
+                        ;; needs to be told where to find the crt files and
+                        ;; the dynamic linker.
+                        (call-with-output-file program
+                          (lambda (p)
+                            (format p "#!~a/bin/bash
 exec ~a/bin/~a-~a -B~a/lib -Wl,-dynamic-linker -Wl,~a/~a \"$@\"~%"
-                                   bash
-                                   gcc triplet program
-                                   libc libc
-                                   ,(glibc-dynamic-linker))))
-
-                       (chmod program #o555))
-
-                     (mkdir-p bindir)
-                     (with-directory-excursion bindir
-                       (for-each (lambda (tool)
-                                   (symlink (string-append binutils "/bin/"
-                                                           triplet "-" tool)
-                                            tool))
-                                 '("ar" "ranlib"))
-                       (for-each wrap-program '("gcc" "g++")))))))
+                                    bash
+                                    gcc triplet program
+                                    libc libc
+                                    #$(glibc-dynamic-linker))))
+
+                        (chmod program #o555))
+
+                      (mkdir-p bindir)
+                      (with-directory-excursion bindir
+                        (for-each (lambda (tool)
+                                    (symlink (string-append binutils "/bin/"
+                                                            triplet "-" tool)
+                                             tool))
+                                  '("ar" "ranlib"))
+                        (for-each wrap-program '("gcc" "g++")))))))
     (native-inputs
      `(("binutils" ,binutils)
        ("gcc" ,gcc)
@@ -3122,79 +3124,80 @@ exec ~a/bin/~a-~a -B~a/lib -Wl,-dynamic-linker -Wl,~a/~a \"$@\"~%"
     (outputs (delete "debug" (package-outputs gcc-boot0)))
 
     (arguments
-     `(#:guile ,%bootstrap-guile
-       #:implicit-inputs? #f
+     (cons*
+      #:guile %bootstrap-guile
+      #:implicit-inputs? #f
 
-       #:allowed-references ("out" "lib" ,zlib-final
+      #:allowed-references `("out" "lib" ,zlib-final
                              ,glibc-final ,static-bash-for-glibc)
 
-       ;; Things like libasan.so and libstdc++.so NEED ld.so for some
-       ;; reason, but it is not in their RUNPATH.  This is a false
-       ;; positive, so turn it off.
-       #:validate-runpath? #f
+      ;; Things like libasan.so and libstdc++.so NEED ld.so for some
+      ;; reason, but it is not in their RUNPATH.  This is a false
+      ;; positive, so turn it off.
+      #:validate-runpath? #f
 
-       ;; Additional modules for the libstdc++ phase below.
-       #:modules ((srfi srfi-1)
+      ;; Additional modules for the libstdc++ phase below.
+      #:modules `((srfi srfi-1)
                   (srfi srfi-26)
                   ,@%gnu-build-system-modules)
 
-       ,@(substitute-keyword-arguments (package-arguments gcc)
-           ((#:make-flags flags)
-            ;; Since $LIBRARY_PATH is not honored, add the relevant flags.
-            `(let ((zlib (assoc-ref %build-inputs "zlib")))
-               (map (lambda (flag)
-                      (if (string-prefix? "LDFLAGS=" flag)
-                          (string-append flag " -L"
-                                         (assoc-ref %build-inputs "libstdc++")
-                                         "/lib -L" zlib "/lib -Wl,-rpath="
-                                         zlib "/lib")
-                          flag))
-                    ,flags)))
-           ;; Build again GMP & co. within GCC's build process, because it's hard
-           ;; to do outside (because GCC-BOOT0 is a cross-compiler, and thus
-           ;; doesn't honor $LIBRARY_PATH, which breaks `gnu-build-system'.)
-           ((#:phases phases)
-            `(modify-phases ,phases
-                (add-after 'unpack 'unpack-gmp&co
-                  (lambda* (#:key inputs #:allow-other-keys)
-                    (let ((gmp  (assoc-ref %build-inputs "gmp-source"))
-                          (mpfr (assoc-ref %build-inputs "mpfr-source"))
-                          (mpc  (assoc-ref %build-inputs "mpc-source")))
-
-                      ;; To reduce the set of pre-built bootstrap inputs, build
-                      ;; GMP & co. from GCC.
-                      (for-each (lambda (source)
-                                  (invoke "tar" "xvf" source))
-                                (list gmp mpfr mpc))
-
-                      ;; Create symlinks like `gmp' -> `gmp-x.y.z'.
-                      ,@(map (lambda (lib)
-                               ;; Drop trailing letters, as gmp-6.0.0a unpacks
-                               ;; into gmp-6.0.0.
-                               `(symlink ,(string-trim-right
+      (substitute-keyword-arguments (package-arguments gcc)
+        ((#:make-flags flags)
+         ;; Since $LIBRARY_PATH is not honored, add the relevant flags.
+         #~(let ((zlib (assoc-ref %build-inputs "zlib")))
+             (map (lambda (flag)
+                    (if (string-prefix? "LDFLAGS=" flag)
+                        (string-append flag " -L"
+                                       (assoc-ref %build-inputs "libstdc++")
+                                       "/lib -L" zlib "/lib -Wl,-rpath="
+                                       zlib "/lib")
+                        flag))
+                  #$flags)))
+        ;; Build again GMP & co. within GCC's build process, because it's hard
+        ;; to do outside (because GCC-BOOT0 is a cross-compiler, and thus
+        ;; doesn't honor $LIBRARY_PATH, which breaks `gnu-build-system'.)
+        ((#:phases phases)
+         #~(modify-phases #$phases
+             (add-after 'unpack 'unpack-gmp&co
+               (lambda* (#:key inputs #:allow-other-keys)
+                 (let ((gmp  (assoc-ref %build-inputs "gmp-source"))
+                       (mpfr (assoc-ref %build-inputs "mpfr-source"))
+                       (mpc  (assoc-ref %build-inputs "mpc-source")))
+
+                   ;; To reduce the set of pre-built bootstrap inputs, build
+                   ;; GMP & co. from GCC.
+                   (for-each (lambda (source)
+                               (invoke "tar" "xvf" source))
+                             (list gmp mpfr mpc))
+
+                   ;; Create symlinks like `gmp' -> `gmp-x.y.z'.
+                   #$@(map (lambda (lib)
+                             ;; Drop trailing letters, as gmp-6.0.0a unpacks
+                             ;; into gmp-6.0.0.
+                             #~(symlink #$(string-trim-right
                                            (package-full-name lib "-")
                                            char-set:letter)
-                                         ,(package-name lib)))
-                             (list gmp-6.0 mpfr mpc)))))
-                (add-after 'unpack 'fix-build-with-external-libstdc++
-                  (lambda* (#:key inputs #:allow-other-keys)
-                    (let ((libstdc++ (assoc-ref inputs "libstdc++")))
-                      ;; Fix a regression in GCC 11 where the libstc++ input
-                      ;; shadows glibc headers when building libstdc++.  An
-                      ;; upstream fix was added in GCC 11.3.0, but it only
-                      ;; hides system include directories, not those on
-                      ;; CPLUS_INCLUDE_PATH.  See discussion at
-                      ;; <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100017>.
-                      (substitute* "libstdc++-v3/src/c++17/Makefile.in"
-                        (("AM_CXXFLAGS = ")
-                         (string-append "CPLUS_INCLUDE_PATH = "
-                                        (string-join
-                                         (remove (cut string-prefix? libstdc++ <>)
-                                                 (string-split
-                                                  (getenv "CPLUS_INCLUDE_PATH")
-                                                  #\:))
-                                         ":")
-                                        "\nAM_CXXFLAGS = ")))))))))))
+                                        #$(package-name lib)))
+                           (list gmp-6.0 mpfr mpc)))))
+             (add-after 'unpack 'fix-build-with-external-libstdc++
+               (lambda* (#:key inputs #:allow-other-keys)
+                 (let ((libstdc++ (assoc-ref inputs "libstdc++")))
+                   ;; Fix a regression in GCC 11 where the libstc++ input
+                   ;; shadows glibc headers when building libstdc++.  An
+                   ;; upstream fix was added in GCC 11.3.0, but it only
+                   ;; hides system include directories, not those on
+                   ;; CPLUS_INCLUDE_PATH.  See discussion at
+                   ;; <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100017>.
+                   (substitute* "libstdc++-v3/src/c++17/Makefile.in"
+                     (("AM_CXXFLAGS = ")
+                      (string-append "CPLUS_INCLUDE_PATH = "
+                                     (string-join
+                                      (remove (cut string-prefix? libstdc++ <>)
+                                              (string-split
+                                               (getenv "CPLUS_INCLUDE_PATH")
+                                               #\:))
+                                      ":")
+                                     "\nAM_CXXFLAGS = ")))))))))))
 
     ;; This time we want Texinfo, so we get the manual.  Add
     ;; STATIC-BASH-FOR-GLIBC so that it's used in the final shebangs of
diff --git a/gnu/packages/gcc.scm b/gnu/packages/gcc.scm
index fade5bb64b..d1c79b8dc2 100644
--- a/gnu/packages/gcc.scm
+++ b/gnu/packages/gcc.scm
@@ -864,62 +864,63 @@ using compilers other than GCC."
     (inherit gcc)
     (name "libstdc++")
     (arguments
-     `(#:out-of-source? #t
-       #:modules ((srfi srfi-1)
+     (list
+      #:out-of-source? #t
+      #:modules `((srfi srfi-1)
                   (srfi srfi-26)
                   ,@%gnu-build-system-modules)
-       #:phases
-       (modify-phases %standard-phases
-         ,@(if (version>=? (package-version gcc) "11")
-               `((add-after 'unpack 'hide-gcc-headers
-                   (lambda* (#:key native-inputs inputs #:allow-other-keys)
-                     (let ((gcc (assoc-ref (or native-inputs inputs)
-                                           ,(if (%current-target-system)
-                                                "cross-gcc"
-                                                "gcc"))))
-                       ;; Fix a regression in GCC 11 where the GCC headers
-                       ;; shadows glibc headers when building libstdc++.  An
-                       ;; upstream fix was added in GCC 11.3.0, but it only
-                       ;; hides system include directories, not those on
-                       ;; CPLUS_INCLUDE_PATH.  See discussion at
-                       ;; <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100017>
-                       ;; and the similar adjustment in GCC-FINAL.
-                       (substitute* "libstdc++-v3/src/c++17/Makefile.in"
-                         (("AM_CXXFLAGS = ")
-                          (string-append ,(if (%current-target-system)
-                                              "CROSS_CPLUS_INCLUDE_PATH = "
-                                              "CPLUS_INCLUDE_PATH = ")
-                                         (string-join
-                                          (remove (cut string-prefix? gcc <>)
-                                                  (string-split
-                                                   (getenv
-                                                    ,(if (%current-target-system)
-                                                         "CROSS_CPLUS_INCLUDE_PATH"
-                                                         "CPLUS_INCLUDE_PATH"))
-                                                   #\:))
-                                          ":")
-                                         "\nAM_CXXFLAGS = ")))))))
-               '())
-         ,@(let ((version (package-version gcc)))
-                (if (and (target-ppc64le?)
-                    (version>=? version "11")
-                    (not (version>=? version "12")))
-               `((add-after 'unpack 'patch-powerpc
-                   (lambda* (#:key inputs #:allow-other-keys)
-                     (invoke "patch" "--force" "-p1" "-i"
-                             (assoc-ref inputs "powerpc64le-patch")))))
-               '()))
-         ;; Force rs6000 (i.e., powerpc) libdir to be /lib and not /lib64.
-         (add-before 'chdir 'fix-rs6000-libdir
-           (lambda _
-             (when (file-exists? "gcc/config/rs6000")
-               (substitute* (find-files "gcc/config/rs6000")
-                 (("/lib64") "/lib")))))
-         (add-before 'configure 'chdir
-           (lambda _
-             (chdir "libstdc++-v3"))))
-
-       #:configure-flags `("--disable-libstdcxx-pch"
+      #:phases
+      #~(modify-phases %standard-phases
+          #$@(if (version>=? (package-version gcc) "11")
+                 #~((add-after 'unpack 'hide-gcc-headers
+                      (lambda* (#:key native-inputs inputs #:allow-other-keys)
+                        (let ((gcc (assoc-ref (or native-inputs inputs)
+                                              #$(if (%current-target-system)
+                                                    "cross-gcc"
+                                                    "gcc"))))
+                          ;; Fix a regression in GCC 11 where the GCC headers
+                          ;; shadows glibc headers when building libstdc++.  An
+                          ;; upstream fix was added in GCC 11.3.0, but it only
+                          ;; hides system include directories, not those on
+                          ;; CPLUS_INCLUDE_PATH.  See discussion at
+                          ;; <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100017>
+                          ;; and the similar adjustment in GCC-FINAL.
+                          (substitute* "libstdc++-v3/src/c++17/Makefile.in"
+                            (("AM_CXXFLAGS = ")
+                             (string-append #$(if (%current-target-system)
+                                                  "CROSS_CPLUS_INCLUDE_PATH = "
+                                                  "CPLUS_INCLUDE_PATH = ")
+                                            (string-join
+                                             (remove (cut string-prefix? gcc <>)
+                                                     (string-split
+                                                      (getenv
+                                                       #$(if (%current-target-system)
+                                                             "CROSS_CPLUS_INCLUDE_PATH"
+                                                             "CPLUS_INCLUDE_PATH"))
+                                                      #\:))
+                                             ":")
+                                            "\nAM_CXXFLAGS = ")))))))
+                 '())
+          #$@(let ((version (package-version gcc)))
+               (if (and (target-ppc64le?)
+                       (version>=? version "11")
+                       (not (version>=? version "12")))
+                   #~((add-after 'unpack 'patch-powerpc
+                        (lambda* (#:key inputs #:allow-other-keys)
+                          (invoke "patch" "--force" "-p1" "-i"
+                                  (assoc-ref inputs "powerpc64le-patch")))))
+                   '()))
+          ;; Force rs6000 (i.e., powerpc) libdir to be /lib and not /lib64.
+          (add-before 'chdir 'fix-rs6000-libdir
+            (lambda _
+              (when (file-exists? "gcc/config/rs6000")
+                (substitute* (find-files "gcc/config/rs6000")
+                  (("/lib64") "/lib")))))
+          (add-before 'configure 'chdir
+            (lambda _
+              (chdir "libstdc++-v3"))))
+
+      #:configure-flags '`("--disable-libstdcxx-pch"
                            ,(string-append "--with-gxx-include-dir="
                                            (assoc-ref %outputs "out")
                                            "/include"))))