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.

libc/stdio/feof.c

@@ -22,7 +22,7 @@
  * Returns true if stream is in end-of-file state.
  *
  * @param f is file object stream pointer
- * @see	feof_unlocked()
+ * @see feof_unlocked()
  */
 int feof(FILE *f) {
   int rc;