small fix for new pthread cleanup stuff

even if pthread_create/exit code is not linked, run flag needs to be
checked and cleanup function potentially run on pop. thus, move the
code to the module that's always linked when pthread_cleanup_push/pop
is used.

src/thread/cancellation.c

@@ -11,6 +11,7 @@ void _pthread_cleanup_push(struct __ptcb *cb, void (*f)(void *), void *x)
 void _pthread_cleanup_pop(struct __ptcb *cb, int run)
 {
 	__do_cleanup_pop(cb, run);
+	if (run) cb->__f(cb->__x);
 }
 
 static void dummy()

src/thread/pthread_create.c

@@ -55,7 +55,6 @@ void __do_cleanup_push(struct __ptcb *cb, void (*f)(void *), void *x)
 void __do_cleanup_pop(struct __ptcb *cb, int run)
 {
 	__pthread_self()->cancelbuf = cb->__next;
-	if (run) cb->__f(cb->__x);
 }
 
 static int start(void *p)