support Android's logging system for fatal_error

Android.bp

@@ -56,6 +56,7 @@ cc_library {
     defaults: ["hardened_malloc_defaults"],
     srcs: lib_src_files,
     export_include_dirs: ["include"],
+    static_libs: ["libasync_safe"],
     target: {
         android: {
             shared: {

util.c

@@ -4,6 +4,10 @@
 
 #include <unistd.h>
 
+#ifdef __ANDROID__
+#include <async_safe/log.h>
+#endif
+
 #include "util.h"
 
 static int write_full(int fd, const char *buf, size_t length) {
@@ -27,5 +31,8 @@ COLD noreturn void fatal_error(const char *s) {
     (void)(write_full(STDERR_FILENO, prefix, strlen(prefix)) != -1 &&
         write_full(STDERR_FILENO, s, strlen(s)) != -1 &&
         write_full(STDERR_FILENO, "\n", 1));
+#ifdef __ANDROID__
+    async_safe_format_log(ANDROID_LOG_FATAL, "hardened_malloc", "fatal allocator error: %s", s);
+#endif
     abort();
 }