gnu: glog: Fix name demangling for GCC 5.

* gnu/packages/patches/glog-gcc-5-demangling.patch: New file.
* gnu/packages/logging.scm (glog)[sources]: Add it.
* gnu/local.mk (dist_patch_DATA): Add it.

3 files changed, 69 insertions, 2 deletions

diff --git a/gnu/local.mk b/gnu/local.mk
index 5da3590375..15087b1183 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -608,6 +608,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/glibc-locales.patch			\
   %D%/packages/patches/glibc-o-largefile.patch			\
   %D%/packages/patches/glibc-versioned-locpath.patch		\
+  %D%/packages/patches/glog-gcc-5-demangling.patch		\
   %D%/packages/patches/gmp-arm-asm-nothumb.patch		\
   %D%/packages/patches/gmp-faulty-test.patch			\
   %D%/packages/patches/gnome-tweak-tool-search-paths.patch	\
diff --git a/gnu/packages/logging.scm b/gnu/packages/logging.scm
index c40d6ebbaf..d28094c3a8 100644
--- a/gnu/packages/logging.scm
+++ b/gnu/packages/logging.scm
@@ -1,6 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2016 Ricardo Wurmus <rekado@elephly.net>
-;;; Copyright © 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -24,6 +24,7 @@
   #:use-module (guix download)
   #:use-module (guix git-download)
   #:use-module (guix build-system gnu)
+  #:use-module (gnu packages)
   #:use-module (gnu packages perl)
   #:use-module (gnu packages autotools))
 
@@ -62,7 +63,8 @@ staying as close to their API as is reasonable.")
               (sha256
                (base32
                 "0ym5g15m7c8kjfr2c3zq6bz08ghin2d1r1nb6v2vnkfh1vn945x1"))
-              (file-name (string-append name "-" version "-checkout"))))
+              (file-name (string-append name "-" version "-checkout"))
+              (patches (search-patches "glog-gcc-5-demangling.patch"))))
     (build-system gnu-build-system)
     (native-inputs
      `(("perl" ,perl)                             ;for tests
diff --git a/gnu/packages/patches/glog-gcc-5-demangling.patch b/gnu/packages/patches/glog-gcc-5-demangling.patch
new file mode 100644
index 0000000000..7f3f42ceca
--- /dev/null
+++ b/gnu/packages/patches/glog-gcc-5-demangling.patch
@@ -0,0 +1,64 @@
+Fix symbol demangling for GCC 5, as reported at:
+
+  https://github.com/google/glog/issues/14
+
+Patch from:
+
+  https://github.com/google/glog/pull/50
+
+From b1639e3014996fbc7635870e013559c54e7e3b2f Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?David=20Mart=C3=ADnez=20Moreno?= <ender@debian.org>
+Date: Thu, 13 Aug 2015 09:31:26 -0700
+Subject: [PATCH] Fix ABI demangling for the GCC 5.x case.
+
+When glog is compiled with gcc-5.2 in cxx11 ABI mode, it barfs about unmangled symbols.  This patches it getting inspiration from binutils and demangle.cc itself, although it may be totally wrong or maybe have to use ParseAbiTag in more places.  I haven't read the spec for the symbols, though.
+
+This patch makes the demangle unit test pass correctly.
+---
+ src/demangle.cc | 19 +++++++++++++++++++
+ 1 file changed, 19 insertions(+)
+
+diff --git a/src/demangle.cc b/src/demangle.cc
+index e858181..0f0c831 100644
+--- a/src/demangle.cc
++++ b/src/demangle.cc
+@@ -439,6 +439,7 @@ static bool ParseExprPrimary(State *state);
+ static bool ParseLocalName(State *state);
+ static bool ParseDiscriminator(State *state);
+ static bool ParseSubstitution(State *state);
++static bool ParseAbiTag(State *state);
+ 
+ // Implementation note: the following code is a straightforward
+ // translation of the Itanium C++ ABI defined in BNF with a couple of
+@@ -567,6 +568,8 @@ static bool ParseNestedName(State *state) {
+ static bool ParsePrefix(State *state) {
+   bool has_something = false;
+   while (true) {
++    if (ParseAbiTag(state))
++      continue;
+     MaybeAppendSeparator(state);
+     if (ParseTemplateParam(state) ||
+         ParseSubstitution(state) ||
+@@ -585,6 +588,22 @@ static bool ParsePrefix(State *state) {
+   return true;
+ }
+ 
++// <abi-tag>          ::= B <source-name>
++static bool ParseAbiTag(State *state) {
++  State copy = *state;
++
++  Append(state, "[", 1);
++  if (ParseOneCharToken(state, 'B') &&
++      ParseSourceName(state))
++  {
++    Append(state, "]", 1);
++    return true;
++  }
++
++  *state = copy;
++  return false;
++}
++
+ // <unqualified-name> ::= <operator-name>
+ //                    ::= <ctor-dtor-name>
+ //                    ::= <source-name>