Fix build and delete superfluous files

- Make Python make formatting pristine
- Add missing `#pragma weak` to Python source
- Fix Clang script flake due to missing directory

tool/build/summy.c

@@ -24,7 +24,11 @@
 
 int main(int argc, char *argv[]) {
   long x, sum = 0;
-  while (scanf("%ld", &x) > 0) sum += x;
+  if (argc == 2 && !strcmp(argv[1], "-x")) {
+    while (scanf("%lx", &x) > 0) sum += x;
+  } else {
+    while (scanf("%ld", &x) > 0) sum += x;
+  }
   printf("%,ld\n", sum);
   return 0;
 }