Fix some warnings

boot/crt0.c

@@ -27,7 +27,7 @@ ISR InitialisationVector[INITIALISATION_VECTOR_SIZE]
   0
 };
 
-void main(int argc, char * argv[]);
+int main(int argc, char * argv[]);
 
 void _start(void) {
   // This is where execution starts after reset.

src/blinky.c

@@ -22,18 +22,18 @@ int main(int argc, char * argv[]) {
   // And we should also set the output speed, but really
   // we don't care (we're doing something super slow)
 
-  long delay = 10000;
+  long delay = 50000;
 
   while (1) {
     GPIO_ODR(GPIOG)->ODR13 = 0;
     GPIO_ODR(GPIOG)->ODR14 = 1;
 
-    sleep(100000);
+    sleep(delay);
 
     GPIO_ODR(GPIOG)->ODR13 = 1;
     GPIO_ODR(GPIOG)->ODR14 = 0;
 
-    sleep(100000);
+    sleep(delay);
   }
 }