more modeline errata (#1019)

Somehow or another, I previously had missed `BUILD.mk` files.

In the process I found a few straggler cases where the modeline was
different from the file, including one very involved manual fix where a
file had been treated like it was ts=2 and ts=8 on separate occasions.

The commit history in the PR shows the gory details; the BUILD.mk was
automated, everything else was mostly manual.

test/libc/runtime/mprotect_test.c

@@ -53,7 +53,7 @@ static const char kRet31337[] = {
 };
 #elif defined(__aarch64__)
 static const uint32_t kRet31337[] = {
-    0x528f4d20,  // mov	w0,#31337
+    0x528f4d20,  // mov w0,#31337
     0xd65f03c0,  // ret
 };
 #else