gnu: glibc: Patch 'openat64', which was buggy on 32-bit platforms.

* gnu/packages/patches/glibc-o-largefile.patch: New file.
* gnu/packages/base.scm (glibc)[source]: Add it to 'patches'.
* gnu-system.am (dist_patch_DATA): Add it.

gnu/packages/patches/glibc-o-largefile.patch

@@ -0,0 +1,25 @@
+This fixes <https://sourceware.org/bugzilla/show_bug.cgi?id=18781>
+whereby, on 32-bit platforms, libc 2.22 would fail to pass O_LARGEFILE
+to 'openat'.  This was caught by 'tests/sparse03.at' in the tar
+test suite.
+
+commit eb32b0d40308166c4d8f6330cc2958cb1e545075
+Author: Andreas Schwab <schwab@suse.de>
+Date:   Mon Aug 10 14:12:47 2015 +0200
+
+    Readd O_LARGEFILE flag for openat64 (bug 18781)
+
+--- a/sysdeps/unix/sysv/linux/openat.c
++++ b/sysdeps/unix/sysv/linux/openat.c
+@@ -68,6 +68,11 @@ __OPENAT (int fd, const char *file, int oflag, ...)
+       va_end (arg);
+     }
+ 
++  /* We have to add the O_LARGEFILE flag for openat64.  */
++#ifdef MORE_OFLAGS
++  oflag |= MORE_OFLAGS;
++#endif
++
+   return SYSCALL_CANCEL (openat, fd, file, oflag, mode);
+ }
+ libc_hidden_def (__OPENAT)