Apply even more fixups

- Finish cleaning up the stdio unlocked APIs
- Make __cxa_finalize() properly thread safe
- Don't log locks if threads aren't being used
- Add some more mutex guards to places using _mmi
- Specific lock names now appear in the --ftrace logs
- Fix mkdeps.com generating invalid Makefiles sometimes
- Simplify and fix bugs in the test runner infrastructure
- Fix issue where sometimes some functions wouldn't be logged

libc/stdio/flushlbf.c

@@ -29,7 +29,7 @@
 void _flushlbf(void) {
   int i;
   FILE *f;
-  pthread_mutex_lock(&__fflush.lock);
+  __fflush_lock();
   for (i = 0; i < __fflush.handles.i; ++i) {
     if ((f = __fflush.handles.p[i])) {
       flockfile(f);
@@ -39,5 +39,5 @@ void _flushlbf(void) {
       funlockfile(f);
     }
   }
-  pthread_mutex_unlock(&__fflush.lock);
+  __fflush_unlock();
 }