Fixes a number of build errors like the following
.../elf32-arm.c: In function 'elf32_arm_nabi_write_core_note':
.../elf32-arm.c:2177: error: #pragma GCC diagnostic not allowed inside functions
.../elf32-arm.c:2186: error: #pragma GCC diagnostic not allowed inside functions
See the comment in diagnostics.h.
include/
* diagnostics.h: Comment on macro usage.
bfd/
* elf32-arm.c (elf32_arm_nabi_write_core_note): Don't use
DIAGNOTIC_PUSH and DIAGNOSTIC_POP unconditionally.
* elf32-ppc.c (ppc_elf_write_core_note): Likewise.
* elf32-s390.c (elf_s390_write_core_note): Likewise.
* elf64-ppc.c (ppc64_elf_write_core_note): Likewise.
* elf64-s390.c (elf_s390_write_core_note): Likewise.
* elfxx-aarch64.c (_bfd_aarch64_elf_write_core_note): Likewise.
(cherry picked from commit fe75810f8e0cc33384f22d0479506711d4014c60)
Move gdb/common/diagnostics.h to include/diagnostics.h so that it can
be used in binutils.
gdb/
* ada-lex.l: Include "diagnostics.h" instead of
"common/diagnostics.h".
* unittests/environ-selftests.c: Likewise.
* common/diagnostics.h: Moved to ../include.
include/
* diagnostics.h: Moved from ../gdb/common/diagnostics.h.