libsanitizer merge from upstream r175049

gcc/ChangeLog

gcc/config/i386/i386.c

gcc/sanitizer.def

gcc/testsuite/ChangeLog

gcc/testsuite/c-c++-common/asan/rlimit-mmap-test-1.c

gcc/testsuite/c-c++-common/asan/strncpy-overflow-1.c

libsanitizer/ChangeLog

libsanitizer/MERGE

libsanitizer/asan/asan_allocator.cc

libsanitizer/asan/asan_allocator.h

libsanitizer/asan/asan_allocator2.cc

libsanitizer/asan/asan_fake_stack.cc

libsanitizer/asan/asan_flags.h

libsanitizer/asan/asan_globals.cc

libsanitizer/asan/asan_intercepted_functions.h

libsanitizer/asan/asan_interceptors.cc

libsanitizer/asan/asan_interceptors.h

libsanitizer/asan/asan_interface_internal.h

libsanitizer/asan/asan_internal.h

libsanitizer/asan/asan_mac.cc