Make improvements

- Introduce ualarm() function
- Make rename() report EISEMPTY on Windows
- Always raise EINVAL upon open(O_RDONLY|O_TRUNC)
- Add macro so ./configure will detect SOCK_CLOEXEC
- Fix O_TRUNC without O_CREAT not working on Windows
- Let fcntl(F_SETFL) change O_APPEND status on Windows
- Make sure pwrite() / pread() report ESPIPE on sockets
- Raise ESPIPE on Windows when pwrite() is used on pipe
- Properly compute O_APPEND CreateFile() flags on Windows
- Don't require O_DIRECTORY to open directories on Windows
- Fix more instances of Windows reporting EISDIR and ENOTDIR
- Normalize EFTYPE and EMLINK to ELOOP on NetBSD and FreeBSD
- Make unlink() / rmdir() work on read-only files on Windows
- Validate UTF-8 on Windows paths to fix bug with overlong NUL
- Always print signal name to stderr when crashing due to SIG_DFL
- Fix Windows bug where denormalized paths >260 chars didn't work
- Block signals on BSDs when thread exits before trashing its own stack

test/libc/calls/unlinkat_test.c

@@ -20,6 +20,7 @@
 #include "libc/dce.h"
 #include "libc/errno.h"
 #include "libc/sysv/consts/at.h"
+#include "libc/sysv/consts/o.h"
 #include "libc/testlib/testlib.h"
 
 char testlib_enable_tmp_setup_teardown;
@@ -45,6 +46,16 @@ TEST(unlink, enotdir) {
   ASSERT_SYS(ENOTDIR, -1, unlink("o/doesnotexist"));
 }
 
+TEST(rmdir, willDeleteRegardlessOfAccessBits) {
+  ASSERT_SYS(0, 0, mkdir("foo", 0));
+  ASSERT_SYS(0, 0, rmdir("foo/"));
+}
+
+TEST(unlink, willDeleteRegardlessOfAccessBits) {
+  ASSERT_SYS(0, 0, touch("foo", 0));
+  ASSERT_SYS(0, 0, unlink("foo"));
+}
+
 TEST(unlinkat, test) {
   int i, fd;
   EXPECT_EQ(0, touch("mytmp", 0644));