configure: move code out of main of check_exec_crash()

Tested-by: Hendrik Leppkes <h.leppkes@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

configure

@@ -845,6 +845,9 @@ check_exec_crash(){
 static void sighandler(int sig){
     raise(SIGTERM);
 }
+int func(void){
+    $code
+}
 int main(void){
     signal(SIGILL, sighandler);
     signal(SIGFPE, sighandler);
@@ -852,7 +855,7 @@ int main(void){
 #ifdef SIGBUS
     signal(SIGBUS, sighandler);
 #endif
-    { $code }
+    return func();
 }
 EOF
 }