glibc: Fix assertion failure when using incompatible locale data

Borrowed from

  http://git.savannah.gnu.org/cgit/guix.git/plain/gnu/packages/patches/glibc-locale-incompatibility.patch

https://github.com/NixOS/nix/issues/599

We may also want to apply

  http://git.savannah.gnu.org/cgit/guix.git/tree/gnu/packages/patches/glibc-versioned-locpath.patch

but we'll need to ditch locale-archive first. (Apparently
locale-archive is not very useful anymore anyway.)

pkgs/development/libraries/glibc/common.nix

@@ -61,6 +61,8 @@ stdenv.mkDerivation ({
       ./security-bdf1ff05.patch
       ./cve-2014-8121.patch
       ./cve-2015-1781.patch
+
+      ./glibc-locale-incompatibility.patch
     ];
 
   postPatch =

pkgs/development/libraries/glibc/glibc-locale-incompatibility.patch

@@ -0,0 +1,25 @@
+http://git.savannah.gnu.org/cgit/guix.git/plain/gnu/packages/patches/glibc-locale-incompatibility.patch
+
+This patch avoids an assertion failure when incompatible locale data
+is encountered:
+
+  https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html
+
+--- glibc-2.22/locale/loadlocale.c	2015-09-22 17:16:02.321981548 +0200
++++ glibc-2.22/locale/loadlocale.c	2015-09-22 17:17:34.814659064 +0200
+@@ -120,10 +120,11 @@
+ 	 _nl_value_type_LC_XYZ array.  There are all pointers.  */
+       switch (category)
+ 	{
+-#define CATTEST(cat) \
+-	case LC_##cat:							      \
+-	  assert (cnt < (sizeof (_nl_value_type_LC_##cat)		      \
+-			 / sizeof (_nl_value_type_LC_##cat[0])));	      \
++#define CATTEST(cat)						\
++	case LC_##cat:						\
++	  if (cnt >= (sizeof (_nl_value_type_LC_##cat)		\
++		      / sizeof (_nl_value_type_LC_##cat[0])))	\
++	    goto puntdata;					\
+ 	  break
+ 	  CATTEST (NUMERIC);
+ 	  CATTEST (TIME);