Clean up more code

- Found some bugs in LLVM compiler-rt library
- The useless LIBC_STUBS package is now deleted
- Improve the overflow checking story even further
- Get chibicc tests working in MODE=dbg mode again
- The libc/isystem/ headers now have correctly named guards

net/http/foldheader.c

@@ -25,7 +25,7 @@
  * Collapses repeating headers onto a single line.
  */
 char *FoldHeader(struct HttpMessage *msg, char *b, int h, size_t *z) {
-  char *p;
+  char *p, *p2;
   size_t i, n, m;
   struct HttpHeader *x;
   n = msg->headers[h].b - msg->headers[h].a;
@@ -35,9 +35,13 @@ char *FoldHeader(struct HttpMessage *msg, char *b, int h, size_t *z) {
       x = msg->xheaders.p + i;
       if (GetHttpHeader(b + x->k.a, x->k.b - x->k.a) == h) {
         m = x->v.b - x->v.a;
-        if (!(p = realloc(p, n + 2 + m))) abort();
-        memcpy(mempcpy(p + n, ", ", 2), b + x->v.a, m);
-        n += 2 + m;
+        if ((p2 = realloc(p, n + 2 + m))) {
+          memcpy(mempcpy((p = p2) + n, ", ", 2), b + x->v.a, m);
+          n += 2 + m;
+        } else {
+          free(p);
+          return 0;
+        }
       }
     }
     *z = n;

net/http/http.mk

@@ -22,7 +22,6 @@ NET_HTTP_A_DIRECTDEPS =				\
 	LIBC_MEM				\
 	LIBC_NEXGEN32E				\
 	LIBC_STR				\
-	LIBC_STUBS				\
 	LIBC_SYSV				\
 	LIBC_TIME