winebuild: Don't remove stdcall decorations on non-x86.

tools/winebuild/utils.c

@@ -664,6 +664,7 @@ int remove_stdcall_decoration( char *name )
 {
     char *p, *end = strrchr( name, '@' );
     if (!end || !end[1] || end == name) return -1;
+    if (target_cpu != CPU_x86) return -1;
     /* make sure all the rest is digits */
     for (p = end + 1; *p; p++) if (!isdigit(*p)) return -1;
     *end = 0;