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/runtime/winmain.greg.c

@@ -98,6 +98,10 @@ static const short kConsoleModes[3] = {
 static uint32_t __init_pid;
 static uint32_t __console_mode[3];
 
+forceinline int IsAlpha(int c) {
+  return ('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z');
+}
+
 // implements all win32 apis on non-windows hosts
 __msabi long __oops_win32(void) {
   assert(!"win32 api called on non-windows host");
@@ -185,6 +189,12 @@ __msabi static textwindows wontreturn void WinMainNew(const char16_t *cmdline) {
       wa->argv[0][i] = '/';
     }
   }
+  if (IsAlpha(wa->argv[0][0]) &&  //
+      wa->argv[0][1] == ':' &&    //
+      wa->argv[0][2] == '/') {
+    wa->argv[0][1] = wa->argv[0][0];
+    wa->argv[0][0] = '/';
+  }
   char16_t *env16 = __imp_GetEnvironmentStringsW();
   GetDosEnviron(env16, wa->envblock, ARRAYLEN(wa->envblock) - 8, wa->envp,
                 ARRAYLEN(wa->envp) - 1);