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/sysv/consts/o.h

@@ -37,6 +37,7 @@ extern const unsigned O_SYNC;
 extern const unsigned O_TMPFILE; /* use tmpfd() or tmpfile() */
 extern const unsigned O_TRUNC;
 extern const unsigned O_TTY_INIT;
+extern const unsigned O_UNLINK;
 extern const unsigned O_VERIFY;
 
 #define O_APPEND     O_APPEND
@@ -58,6 +59,7 @@ extern const unsigned O_VERIFY;
 #define O_SEQUENTIAL O_SEQUENTIAL
 #define O_SYNC       O_SYNC
 #define O_TRUNC      O_TRUNC
+#define O_UNLINK     O_UNLINK
 
 COSMOPOLITAN_C_END_
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */