gnu: gcc@4.8: Fix libsanitizer build issue.

Fixes <https://bugs.gnu.org/32397>.
Reported by fis trivial <ybbs.daans@hotmail.com>.

* gnu/packages/patches/gcc-4.8-libsanitizer-fix.patch: New file.
* gnu/packages/gcc.scm (gcc-4.8)[source]: Use it.
* gnu/local.mk (dist_patch_DATA): Add it.

gnu/local.mk

@@ -695,6 +695,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/gcc-asan-missing-include.patch		\
   %D%/packages/patches/gcc-cross-environment-variables.patch	\
   %D%/packages/patches/gcc-fix-texi2pod.patch			\
+  %D%/packages/patches/gcc-4.8-libsanitizer-fix.patch		\
   %D%/packages/patches/gcc-4.9-libsanitizer-fix.patch		\
   %D%/packages/patches/gcc-libsanitizer-fix.patch		\
   %D%/packages/patches/gcc-libvtv-runpath.patch			\

gnu/packages/gcc.scm

@@ -365,6 +365,7 @@ Go.  It also includes runtime support libraries for these languages.")
                (base32
                 "08yggr18v373a1ihj0rg2vd6psnic42b518xcgp3r9k81xz1xyr2"))
               (patches (search-patches "gcc-arm-link-spec-fix.patch"
+                                       "gcc-4.8-libsanitizer-fix.patch"
                                        "gcc-asan-missing-include.patch"
                                        "gcc-fix-texi2pod.patch"))
               (modules '((guix build utils)))

gnu/packages/patches/gcc-4.8-libsanitizer-fix.patch

@@ -0,0 +1,15 @@
+This is a backport of part of this patch from 6.5 to 4.8:
+
+  https://gcc.gnu.org/git/?p=gcc.git;a=patch;h=8937b94d1a643fd9760714642296d034a45254a8
+
+--- a/libsanitizer/tsan/tsan_platform_linux.cc
++++ b/libsanitizer/tsan/tsan_platform_linux.cc
+@@ -351,7 +351,7 @@ bool IsGlobalVar(uptr addr) {
+ // closes within glibc. The code is a pure hack.
+ int ExtractResolvFDs(void *state, int *fds, int nfd) {
+   int cnt = 0;
+-  __res_state *statp = (__res_state*)state;
++  struct __res_state *statp = (struct __res_state*)state;
+   for (int i = 0; i < MAXNS && cnt < nfd; i++) {
+     if (statp->_u._ext.nsaddrs[i] && statp->_u._ext.nssocks[i] != -1)
+       fds[cnt++] = statp->_u._ext.nssocks[i];