Fix warnings

This change fixes Cosmopolitan so it has fewer opinions about compiler
warnings. The whole repository had to be cleaned up to be buildable in
-Werror -Wall mode. This lets us benefit from things like strict const
checking. Some actual bugs might have been caught too.

net/http/indentlines.c

@@ -33,7 +33,7 @@
 char *IndentLines(const char *p, size_t n, size_t *z, size_t j) {
   char *r, *q;
   const char *l;
-  size_t i, t, m, a;
+  size_t t, m, a;
   if (n == -1) n = p ? strlen(p) : 0;
   r = 0;
   t = 0;