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/tool/net/redbean_test.c

@@ -126,6 +126,7 @@ TEST(redbean, testOptions) {
                       "Content-Length: 0\r\n"
                       "\r\n",
                       gc(SendHttpRequest("OPTIONS * HTTP/1.1\n\n"))));
+  EXPECT_EQ(0, close(pipefds[0]));
   EXPECT_NE(-1, kill(pid, SIGTERM));
   EXPECT_NE(-1, wait(0));
   CHECK_NE(-1, sigprocmask(SIG_SETMASK, &savemask, 0));
@@ -169,6 +170,7 @@ TEST(redbean, testPipeline) {
                       "\r\n",
                       gc(SendHttpRequest("OPTIONS * HTTP/1.1\n\n"
                                          "OPTIONS * HTTP/1.1\n\n"))));
+  EXPECT_EQ(0, close(pipefds[0]));
   EXPECT_NE(-1, kill(pid, SIGTERM));
   EXPECT_NE(-1, wait(0));
   CHECK_NE(-1, sigprocmask(SIG_SETMASK, &savemask, 0));