[gcc r12-780] libsanitizer, Darwin : Handle missing __builtin_os_log_format.

[Iain D Sandoe <iains@gcc.gnu.org>]

https://gcc.gnu.org/g:adab7b2bf42b469e51154a09a1b4fa0726a7073c

commit r12-780-gadab7b2bf42b469e51154a09a1b4fa0726a7073c
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Thu May 13 19:43:09 2021 +0100

    libsanitizer, Darwin : Handle missing __builtin_os_log_format.
    
    GCC does not, currently, define __builtin_os_log_format, which
    is needed by os/log.h.  Do not include that header unless the
    builtin is defined (since the header errors out on the same
    condition).  Provide a work-around solution to the missing API
    provided via the header.
    
    libsanitizer/ChangeLog:
    
            * sanitizer_common/sanitizer_mac.cpp : Check for the
            availability of __builtin_os_log_format before trying to
            include a header depending on it.
            (OS_LOG_DEFAULT): New.
            (os_log_error): Define to a fall-back using an older API.

Diff:
---
 libsanitizer/sanitizer_common/sanitizer_mac.cpp | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/libsanitizer/sanitizer_common/sanitizer_mac.cpp b/libsanitizer/sanitizer_common/sanitizer_mac.cpp
index f455856c85d..30a94fcba14 100644
--- a/libsanitizer/sanitizer_common/sanitizer_mac.cpp
+++ b/libsanitizer/sanitizer_common/sanitizer_mac.cpp
@@ -70,7 +70,15 @@ extern "C" {
 #include <mach/mach_time.h>
 #include <mach/vm_statistics.h>
 #include <malloc/malloc.h>
-#include <os/log.h>
+#if defined(__has_builtin) && __has_builtin(__builtin_os_log_format)
+# include <os/log.h>
+#else
+   /* Without support for __builtin_os_log_format, fall back to the older
+      method.  */
+# define OS_LOG_DEFAULT 0
+# define os_log_error(A,B,C) \
+  asl_log(nullptr, nullptr, ASL_LEVEL_ERR, "%s", (C));
+#endif
 #include <pthread.h>
 #include <sched.h>
 #include <signal.h>