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/thread/thread.mk

@@ -28,6 +28,7 @@ LIBC_THREAD_A_DIRECTDEPS =			\
 	LIBC_CALLS				\
 	LIBC_INTRIN				\
 	LIBC_BITS				\
+	LIBC_MEM				\
 	LIBC_RUNTIME				\
 	LIBC_SYSV				\
 	LIBC_SYSV_CALLS				\
@@ -36,7 +37,8 @@ LIBC_THREAD_A_DIRECTDEPS =			\
 LIBC_THREAD_A_DEPS :=				\
 	$(call uniq,$(foreach x,$(LIBC_THREAD_A_DIRECTDEPS),$($(x))))
 
-$(LIBC_THREAD_A):	libc/thread/		\
+$(LIBC_THREAD_A):				\
+		libc/thread/			\
 		$(LIBC_THREAD_A).pkg		\
 		$(LIBC_THREAD_A_OBJS)
 
@@ -44,6 +46,10 @@ $(LIBC_THREAD_A).pkg:				\
 		$(LIBC_THREAD_A_OBJS)		\
 		$(foreach x,$(LIBC_THREAD_A_DIRECTDEPS),$($(x)_A).pkg)
 
+o/$(MODE)/libc/thread/clone.o:			\
+		OVERRIDE_CFLAGS +=		\
+			-mno-red-zone
+
 LIBC_THREAD_LIBS = $(foreach x,$(LIBC_THREAD_ARTIFACTS),$($(x)))
 LIBC_THREAD_SRCS = $(foreach x,$(LIBC_THREAD_ARTIFACTS),$($(x)_SRCS))
 LIBC_THREAD_HDRS = $(foreach x,$(LIBC_THREAD_ARTIFACTS),$($(x)_HDRS))