go/gospec: forcibly disable -fsplit-stack support

for some reason, TARGET_CAN_SPLIT_STACK still gets defined on 32-bit x86,
so hackfix it for now

gcc/go/gospec.c

@@ -269,11 +269,12 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options,
   /* Copy the 0th argument, i.e., the name of the program itself.  */
   new_decoded_options[j++] = decoded_options[i++];
 
-#ifdef TARGET_CAN_SPLIT_STACK
+  /* Hackfix: we never support split stack on Alpine GCC */
+#if 0
   supports_split_stack = 1;
 #endif
 
-#ifdef TARGET_CAN_SPLIT_STACK_64BIT
+#if 0
   if (is_m64)
     supports_split_stack = 1;
 #endif