[sanitizer] Revert rL318410

[cryptoad]

Summary

The patch seems to have turned some Android tests flaky. The reason is unclear.
This reverts D40100 in case we can't figure out what is happening.

[cryptoad]

Rebasing.

lib/sanitizer_common/sanitizer_linux_libcdep.cc

 #if SANITIZER_LINUX
 #include <sys/prctl.h>
 #endif
 
 #if SANITIZER_ANDROID
 #include <android/api-level.h>
 #endif
 
+#if SANITIZER_ANDROID && __ANDROID_API__ < 21
+#include <android/log.h>
+#endif
+
 #if !SANITIZER_ANDROID
 #include <elf.h>
 #include <unistd.h>
 #endif
 
 namespace __sanitizer {
 
 SANITIZER_WEAK_ATTRIBUTE int
while (!(*pos >= '0' && *pos <= '9') && *pos != 0)
     pos++;
   // Read the number.
   uptr rss = 0;
   while (*pos >= '0' && *pos <= '9')
     rss = rss * 10 + *pos++ - '0';
   return rss * GetPageSizeCached();
 }
 
+// 64-bit Android targets don't provide the deprecated __android_log_write.
+// Starting with the L release, syslog() works and is preferable to
+// __android_log_write.
 #if SANITIZER_LINUX
 
-# if SANITIZER_ANDROID
+#if SANITIZER_ANDROID
 static atomic_uint8_t android_log_initialized;
 
 void AndroidLogInit() {
   openlog(GetProcessName(), 0, LOG_USER);
   atomic_store(&android_log_initialized, 1, memory_order_release);
 }
 
 static bool ShouldLogAfterPrintf() {
   return atomic_load(&android_log_initialized, memory_order_acquire);
 }
-
-extern "C" SANITIZER_WEAK_ATTRIBUTE
-int async_safe_write_log(int pri, const char* tag, const char* msg);
-extern "C" SANITIZER_WEAK_ATTRIBUTE
-int __android_log_write(int prio, const char* tag, const char* msg);
-
-// ANDROID_LOG_INFO is 4, but can't be resolved at runtime.
-#define SANITIZER_ANDROID_LOG_INFO 4
-
-// async_safe_write_log is basically __android_log_write but is only available
-// in recent versions of Bionic. __android_log_write was deprecated along the
-// way, so fallback to syslog if neither exists. The non-syslog alternatives
-// do not allocate memory and are preferable. Also syslog is broken pre-L, this
-// is another reason why we prefer __android_log_write if available.
-void WriteOneLineToSyslog(const char *s) {
-  if (&async_safe_write_log) {
-    async_safe_write_log(SANITIZER_ANDROID_LOG_INFO, GetProcessName(), s);
-  } else if (&__android_log_write) {
-    __android_log_write(SANITIZER_ANDROID_LOG_INFO, nullptr, s);
-  } else {
-    syslog(LOG_INFO, "%s", s);
-  }
-}
-
-extern "C" SANITIZER_WEAK_ATTRIBUTE
-void android_set_abort_message(const char *);
-
-void SetAbortMessage(const char *str) {
-  if (&android_set_abort_message)
-    android_set_abort_message(str);
-}
-# else
+#else
 void AndroidLogInit() {}
 
 static bool ShouldLogAfterPrintf() { return true; }
-
-void WriteOneLineToSyslog(const char *s) { syslog(LOG_INFO, "%s", s); }
-
-void SetAbortMessage(const char *str) {}
-# endif  // SANITIZER_ANDROID
+#endif  // SANITIZER_ANDROID
 
+void WriteOneLineToSyslog(const char *s) {
+#if SANITIZER_ANDROID &&__ANDROID_API__ < 21
+  __android_log_write(ANDROID_LOG_INFO, NULL, s);
+#else
+  syslog(LOG_INFO, "%s", s);
+#endif
+}
+
 void LogMessageOnPrintf(const char *str) {
   if (common_flags()->log_to_syslog && ShouldLogAfterPrintf())
     WriteToSyslog(str);
 }
 
-#endif  // SANITIZER_LINUX
+#if SANITIZER_ANDROID
+extern "C" __attribute__((weak)) void android_set_abort_message(const char *);
+void SetAbortMessage(const char *str) {
+  if (&android_set_abort_message) android_set_abort_message(str);
+}
+#else
+void SetAbortMessage(const char *str) {}
+#endif
+
+#endif // SANITIZER_LINUX
 
 } // namespace __sanitizer
 
 #endif // SANITIZER_FREEBSD || SANITIZER_LINUX