Fix bugs and make improvements

- Get clone() working on FreeBSD
- Increase some Python build quotas
- Add more atomic builtins to chibicc
- Fix ASAN poisoning of alloca() memory
- Make MODE= mandatory link path tinier
- Improve the examples folder a little bit
- Start working on some more resource limits
- Make the linenoise auto-complete UI as good as GNU readline
- Update compile.com, avoiding AVX codegen on non-AVX systems
- Make sure empty path to syscalls like opendir raises ENOENT
- Correctly polyfill ENOENT vs. ENOTDIR on the New Technology
- Port bestline's paredit features to //third_party/linenoise
- Remove workarounds for RHEL 5.0 bugs that were fixed in 5.1

libc/calls/getfilesize.c

@@ -28,7 +28,7 @@
  * Returns the byte length of file by path.
  *
  * @return number of bytes, or -1ul w/ errno
- * @see getfiledescriptorsize
+ * @see getfiledescriptorsize()
  */
 size_t GetFileSize(const char *pathname) {
   struct stat st;