Use _Fork().

POSIX issue 8 has a standard way to avoid pthread_atfork() handlers.

Change-Id: I801c55dc3fb9e14cc03f854992d60872c5468ab5
diff --git a/debuggerd/handler/debuggerd_handler.cpp b/debuggerd/handler/debuggerd_handler.cpp
index 141723b..595f373 100644
--- a/debuggerd/handler/debuggerd_handler.cpp
+++ b/debuggerd/handler/debuggerd_handler.cpp
@@ -275,10 +275,6 @@
   }
 }
 
-static pid_t __fork() {
-  return clone(nullptr, nullptr, 0, nullptr);
-}
-
 // Double-clone, with CLONE_FILES to share the file descriptor table for kcmp validation.
 // Returns 0 in the orphaned child, the pid of the orphan in the original process, or -1 on failure.
 static void create_vm_process() {
@@ -426,7 +422,7 @@
   }
 
   // Don't use fork(2) to avoid calling pthread_atfork handlers.
-  pid_t crash_dump_pid = __fork();
+  pid_t crash_dump_pid = _Fork();
   if (crash_dump_pid == -1) {
     async_safe_format_log(ANDROID_LOG_FATAL, "libc",
                           "failed to fork in debuggerd signal handler: %s", strerror(errno));