Make improvements

- Invent openatemp() API
- Invent O_UNLINK open flag
- Introduce getenv_secure() API
- Remove `git pull` from cosmocc
- Fix utimes() when path is NULL
- Fix mktemp() to never return NULL
- Fix utimensat() UTIME_OMIT on XNU
- Improve utimensat() code for RHEL5
- Turn `argv[0]` C:/ to /C/ on Windows
- Introduce tmpnam() and tmpnam_r() APIs
- Fix more const issues with internal APIs
- Permit utimes() on WIN32 in O_RDONLY mode
- Fix fdopendir() to check fd is a directory
- Fix recent crash regression in landlock make
- Fix futimens(AT_FDCWD, NULL) to return EBADF
- Use workaround so `make -j` doesn't fork bomb
- Rename dontdiscard to __wur (just like glibc)
- Fix st_size for WIN32 symlinks containing UTF-8
- Introduce stdio ext APIs needed by GNU coreutils
- Fix lstat() on WIN32 for symlinks to directories
- Move some constants from normalize.inc to limits.h
- Fix segv with memchr() and memcmp() overlapping page
- Implement POSIX fflush() behavior for reader streams
- Implement AT_SYMLINK_NOFOLLOW for utimensat() on WIN32
- Don't change read-only status of existing files on WIN32
- Correctly handle `0x[^[:xdigit:]]` case in strtol() functions

libc/calls/futimens.c

@@ -44,7 +44,11 @@
  */
 int futimens(int fd, const struct timespec ts[2]) {
   int rc;
-  rc = __utimens(fd, 0, ts, 0);
+  if (fd < 0) {
+    rc = ebadf();  // so we don't confuse __utimens if caller passes AT_FDCWD
+  } else {
+    rc = __utimens(fd, 0, ts, 0);
+  }
   STRACE("futimens(%d, {%s, %s}) → %d% m", fd, DescribeTimespec(0, ts),
          DescribeTimespec(0, ts ? ts + 1 : 0), rc);
   return rc;