gnu: GCC@8: Remove obsolete patch.

This is no longer required since the update to 8.4.0 in 60ce496ad8.

* gnu/packages/patches/gcc-8-libsanitizer-mode-size.patch: Delete file.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/gcc.scm (gcc-8)[source](patches): Remove it.

gnu/local.mk

@@ -924,7 +924,6 @@ dist_patch_DATA =						\
   %D%/packages/patches/gcc-4.9-libsanitizer-mode-size.patch	\
   %D%/packages/patches/gcc-6-libsanitizer-mode-size.patch	\
   %D%/packages/patches/gcc-7-libsanitizer-mode-size.patch	\
-  %D%/packages/patches/gcc-8-libsanitizer-mode-size.patch	\
   %D%/packages/patches/gcc-libvtv-runpath.patch			\
   %D%/packages/patches/gcc-strmov-store-file-names.patch	\
   %D%/packages/patches/gcc-4-compile-with-gcc-5.patch		 \

gnu/packages/gcc.scm

@@ -547,7 +547,6 @@ It also includes runtime support libraries for these languages.")))
                (base32
                 "1m1d3gfix56w4aq8myazzfffkl8bqcrx4jhhapnjf7qfs596w2p3"))
               (patches (search-patches "gcc-8-strmov-store-file-names.patch"
-                                       "gcc-8-libsanitizer-mode-size.patch"
                                        "gcc-5.0-libvtv-runpath.patch"))))))
 
 (define-public gcc-9

gnu/packages/patches/gcc-8-libsanitizer-mode-size.patch

@@ -1,56 +0,0 @@
-Fix assertion failure in libsanitizer when using glibc 2.31 and later.
-
-https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92154
-https://reviews.llvm.org/D69104
-
-Adapted from these upstream revision:
-
-https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=277981
-https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=279653
-
-diff --git a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
-index a915d37cdfe..5c720b2e700 100644
---- a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
-+++ b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
-@@ -1147,8 +1147,9 @@ CHECK_SIZE_AND_OFFSET(ipc_perm, uid);
- CHECK_SIZE_AND_OFFSET(ipc_perm, gid);
- CHECK_SIZE_AND_OFFSET(ipc_perm, cuid);
- CHECK_SIZE_AND_OFFSET(ipc_perm, cgid);
--#if !defined(__aarch64__) || !SANITIZER_LINUX || __GLIBC_PREREQ (2, 21)
--/* On aarch64 glibc 2.20 and earlier provided incorrect mode field.  */
-+#if !SANITIZER_LINUX || __GLIBC_PREREQ (2, 31)
-+/* glibc 2.30 and earlier provided 16-bit mode field instead of 32-bit
-+   on many architectures.  */
- CHECK_SIZE_AND_OFFSET(ipc_perm, mode);
- #endif
- 
-diff --git a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h
-index 4d11d071776..eda75a7cd84 100644
---- a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h
-+++ b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h
-@@ -210,14 +210,8 @@ namespace __sanitizer {
-     u64 __unused1;
-     u64 __unused2;
- #elif defined(__sparc__)
--#if defined(__arch64__)
-     unsigned mode;
--    unsigned short __pad1;
--#else
--    unsigned short __pad1;
--    unsigned short mode;
-     unsigned short __pad2;
--#endif
-     unsigned short __seq;
-     unsigned long long __unused1;
-     unsigned long long __unused2;
-@@ -228,8 +222,7 @@ namespace __sanitizer {
-     unsigned long __unused1;
-     unsigned long __unused2;
- #else
--    unsigned short mode;
--    unsigned short __pad1;
-+    unsigned int mode;
-     unsigned short __seq;
-     unsigned short __pad2;
- #if defined(__x86_64__) && !defined(_LP64)
-