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

test/libc/thread/clone_test.c

@@ -0,0 +1,57 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2021 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/dce.h"
+#include "libc/intrin/spinlock.h"
+#include "libc/sysv/consts/clone.h"
+#include "libc/testlib/testlib.h"
+
+int x, thechilde;
+_Alignas(64) volatile char lock;
+
+void SetUp(void) {
+  x = 0;
+  lock = 0;
+  thechilde = 0;
+}
+
+int thread(void *arg) {
+  x = 42;
+  ASSERT_EQ(23, (intptr_t)arg);
+  thechilde = gettid();
+  _spunlock(&lock);
+  return 0;
+}
+
+TEST(clone, test) {
+  if (IsXnu()) return;
+  if (IsOpenbsd()) return;  // still flaky :'(
+  int me, tid;
+  char *stack;
+  me = gettid();
+  _spinlock(&lock);
+  stack = _gc(valloc(STACKSIZE));
+  ASSERT_NE(-1, (tid = clone(thread, stack, STACKSIZE,
+                             CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND,
+                             (void *)23, 0, 0, 0, 0)));
+  _spinlock(&lock);
+  ASSERT_EQ(42, x);
+  ASSERT_NE(me, tid);
+  ASSERT_EQ(tid, thechilde);
+}

test/libc/thread/test.mk

@@ -0,0 +1,71 @@
+#-*-mode:makefile-gmake;indent-tabs-mode:t;tab-width:8;coding:utf-8-*-┐
+#───vi: set et ft=make ts=8 tw=8 fenc=utf-8 :vi───────────────────────┘
+
+PKGS += TEST_LIBC_THREAD
+
+TEST_LIBC_THREAD_SRCS := $(wildcard test/libc/thread/*.c)
+TEST_LIBC_THREAD_SRCS_TEST = $(filter %_test.c,$(TEST_LIBC_THREAD_SRCS))
+
+TEST_LIBC_THREAD_OBJS =					\
+	$(TEST_LIBC_THREAD_SRCS:%.c=o/$(MODE)/%.o)
+
+TEST_LIBC_THREAD_COMS =					\
+	$(TEST_LIBC_THREAD_SRCS:%.c=o/$(MODE)/%.com)
+
+TEST_LIBC_THREAD_BINS =					\
+	$(TEST_LIBC_THREAD_COMS)			\
+	$(TEST_LIBC_THREAD_COMS:%=%.dbg)
+
+TEST_LIBC_THREAD_TESTS =				\
+	$(TEST_LIBC_THREAD_SRCS_TEST:%.c=o/$(MODE)/%.com.ok)
+
+TEST_LIBC_THREAD_CHECKS =				\
+	$(TEST_LIBC_THREAD_SRCS_TEST:%.c=o/$(MODE)/%.com.runs)
+
+TEST_LIBC_THREAD_DIRECTDEPS =				\
+	LIBC_CALLS					\
+	LIBC_FMT					\
+	LIBC_INTRIN					\
+	LIBC_MEM					\
+	LIBC_NEXGEN32E					\
+	LIBC_RUNTIME					\
+	LIBC_STR					\
+	LIBC_STUBS					\
+	LIBC_SYSV					\
+	LIBC_THREAD					\
+	LIBC_TESTLIB
+
+TEST_LIBC_THREAD_DEPS :=				\
+	$(call uniq,$(foreach x,$(TEST_LIBC_THREAD_DIRECTDEPS),$($(x))))
+
+o/$(MODE)/test/libc/thread/thread.pkg:			\
+		$(TEST_LIBC_THREAD_OBJS)		\
+		$(foreach x,$(TEST_LIBC_THREAD_DIRECTDEPS),$($(x)_A).pkg)
+
+o/$(MODE)/test/libc/thread/%.com.dbg:			\
+		$(TEST_LIBC_THREAD_DEPS)		\
+		o/$(MODE)/test/libc/thread/%.o		\
+		o/$(MODE)/test/libc/thread/thread.pkg	\
+		$(LIBC_TESTMAIN)			\
+		$(CRT)					\
+		$(APE)
+	@$(APELINK)
+
+$(TEST_LIBC_THREAD_OBJS):				\
+	DEFAULT_CCFLAGS +=				\
+		-fno-builtin
+
+o/$(MODE)/test/libc/thread/getenv_test.com.runs:	\
+		o/$(MODE)/test/libc/thread/getenv_test.com
+	@HELLO=THERE build/runit $@ $<
+
+o/$(MODE)/test/libc/thread/fun_test.o			\
+o/$(MODE)/test/libc/thread/itsatrap_test.o:		\
+		OVERRIDE_CFLAGS +=			\
+			-fno-sanitize=all		\
+			-ftrapv
+
+.PHONY: o/$(MODE)/test/libc/thread
+o/$(MODE)/test/libc/thread:				\
+		$(TEST_LIBC_THREAD_BINS)		\
+		$(TEST_LIBC_THREAD_CHECKS)