[sanitizer_common] Restore sanitizer_procmaps_solaris.cpp compilation on Solaris 11.3

[ro]

Summary

When upstream compiler-rt was recently imported into GCC's libsanitizer, Solaris 11.3 bootstrap broke because in 11.3 <sys/procfs.h> doesn't mix with largefile compilation. I'd caused this in D129837 where I forgot that the code still needs to support Solaris 11.3.

Fixed by restoring the #undef _FILE_OFFSET_BITS.

Tested on sparc-sun-solaris2.11 and amd64-pc-solaris2.11 (Solaris 11.4) in LLVM and both Solaris 11.3 and 11.4 in GCC.

[ro]

Ping? It's been a weed and a half.

[vitalybuka]

Sorry for delay.

[ro]

No worries: I could easily keep the patch local to gcc for a while, and LLVM isn't affected anyway (apart from the staging buildmaster being down for more than a week).

compiler-rt/lib/sanitizer_common/sanitizer_procmaps_solaris.cpp

 //===-- sanitizer_procmaps_solaris.cpp ------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // Information about the process mappings (Solaris-specific parts).
 //===----------------------------------------------------------------------===//
 
+// Before Solaris 11.4, <procfs.h> doesn't work in a largefile environment.
+#undef _FILE_OFFSET_BITS
 #include "sanitizer_platform.h"
 #if SANITIZER_SOLARIS
 #  include <fcntl.h>
 #  include <limits.h>
 #  include <procfs.h>
 
 #  include "sanitizer_common.h"
 #  include "sanitizer_procmaps.h"