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/intrin/spinlock.h

@@ -1,9 +1,14 @@
 #ifndef COSMOPOLITAN_LIBC_INTRIN_SPINLOCK_H_
 #define COSMOPOLITAN_LIBC_INTRIN_SPINLOCK_H_
-#if !(__ASSEMBLER__ + __LINKER__ + 0)
-#if (__GNUC__ + 0) * 100 + (__GNUC_MINOR__ + 0) >= 401 && \
-    !defined(__STRICT_ANSI__)
 
+#ifdef TINY
+#define _spinlock(lock)                         \
+  do {                                          \
+    while (__sync_lock_test_and_set(lock, 1)) { \
+      __builtin_ia32_pause();                   \
+    }                                           \
+  } while (0)
+#else
 #define _spinlock(lock)                               \
   do {                                                \
     for (;;) {                                        \
@@ -16,9 +21,8 @@
       }                                               \
     }                                                 \
   } while (0)
+#endif
 
 #define _spunlock(lock) __sync_lock_release(lock)
 
-#endif /* GNU 4.1+ */
-#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
 #endif /* COSMOPOLITAN_LIBC_INTRIN_SPINLOCK_H_ */