3 files changed, 43 insertions, 7 deletions
diff --git a/gnu/build/cross-toolchain.scm b/gnu/build/cross-toolchain.scm
index 9746be3e50..da9016488f 100644
--- a/gnu/build/cross-toolchain.scm
+++ b/gnu/build/cross-toolchain.scm
@@ -48,6 +48,12 @@
   ;; Search path for target headers when cross-compiling.
   (map (cut string-append "CROSS_" <>) %gcc-include-paths))
 
+(define* (patch-genmultilib-shebang #:key inputs native-inputs #:allow-other-keys)
+  "Patch-shebang in the gcc/genmultilib file doesn't work as it contains several
+scripts inside, each with a #!/bin/sh that needs patching."
+  (substitute* "gcc/genmultilib"
+    (("#!/bin/sh") (string-append "#!" (which "sh")))))
+
 (define* (make-cross-binutils-visible #:key outputs inputs target
                                       #:allow-other-keys)
   "Create symlinks for 'as', 'nm', and 'ld' in the \"out\" output, under
@@ -162,6 +168,31 @@ C_*INCLUDE_PATH."
               (cons "LIBRARY_PATH" %gcc-include-paths))
     #t))
 
+(define* (set-cross-path/avr #:key inputs #:allow-other-keys)
+  (match (assoc-ref inputs "libc")
+    ((? string? libc)
+     (define (cross? x)
+       ;; Return #t if X is a cross-libc.
+       (string-prefix? libc x))
+
+     (let ((cpath (string-append libc "/avr/include")))
+       (for-each (cut setenv <> cpath)
+                 %gcc-cross-include-paths))
+
+     (setenv "CROSS_LIBRARY_PATH"
+             (string-append libc "/avr/lib"))
+
+     (for-each (lambda (var)
+                   (and=> (getenv var)
+                          (lambda (value)
+                            (let* ((path (search-path-as-string->list value))
+                                   (native-path (list->search-path-as-string
+                                                 (remove cross? path) ":")))
+                              (setenv var native-path)))))
+                 (cons "LIBRARY_PATH" %gcc-include-paths)))
+    ;; AVR sans-libc cross-compiler.
+    (else #t)))
+
 (define (install-strip . _)
   "Install a stripped GCC."
   ;; Unlike our 'strip' phase, this will do the right thing for
@@ -173,14 +204,18 @@ C_*INCLUDE_PATH."
   "Modify PHASES to include everything needed to build a cross-GCC for TARGET,
 a target triplet."
   (modify-phases phases
+    (add-after 'unpack 'patch-genmultilib-shebang
+      patch-genmultilib-shebang)
     (add-before 'configure 'set-cross-path
       ;; This mingw32 target checking logic should match that of target-mingw?
       ;; in (guix utils), but (guix utils) is too large too copy over to the
       ;; build side entirely and for now we have no way to select variables to
       ;; copy over. See (gnu packages cross-base) for more details.
-      (if (string-suffix? "-mingw32" target)
-          (cut set-cross-path/mingw #:target target <...>)
-          set-cross-path))
+      (cond
+        ((string-suffix? "-mingw32" target)
+         (cut set-cross-path/mingw #:target target <...>))
+        ((string-prefix? "avr" target) set-cross-path/avr)
+        (#t set-cross-path)))
     (add-after 'install 'make-cross-binutils-visible
       (cut make-cross-binutils-visible #:target target <...>))
     (replace 'install install-strip)))
diff --git a/gnu/build/icecat-extension.scm b/gnu/build/icecat-extension.scm
index 1e6a9a54e4..e6927c79df 100644
--- a/gnu/build/icecat-extension.scm
+++ b/gnu/build/icecat-extension.scm
@@ -29,6 +29,7 @@ when installed, will make the extension contained in PKG available as an
 Icecat browser extension.  PKG-OUTPUT specifies which output of PKG to use."
   (package
     (inherit pkg)
+    (location (package-location pkg))
     (name (string-append (package-name pkg) "-icecat"))
     (native-inputs '())
     (inputs '())
diff --git a/gnu/build/linux-boot.scm b/gnu/build/linux-boot.scm
index 84726363c0..548e28a1c9 100644
--- a/gnu/build/linux-boot.scm
+++ b/gnu/build/linux-boot.scm
@@ -611,10 +611,6 @@ upon error."
 the root file system...\n" root-delay)
             (sleep root-delay)))
 
-        ;; Prepare the real root file system under /root.
-        (unless (file-exists? "/root")
-          (mkdir "/root"))
-
         (when (procedure? pre-mount)
           ;; Do whatever actions are needed before mounting the root file
           ;; system--e.g., installing device mappings.  Error out when the
@@ -631,6 +627,10 @@ the root file system...\n" root-delay)
           (false-if-exception           ; failure is not fatal
            (resume-if-hibernated (find-long-option "resume" args))))
 
+        ;; Prepare the real root file system under /root.
+        (unless (file-exists? "/root")
+          (mkdir "/root"))
+
         (setenv "EXT2FS_NO_MTAB_OK" "1")
 
         ;; Mount the root file system.