Do not check for MiNT cookie when setting the rootdir

MagiC also has a U:\ drive

Author: th-otto

mintlib/main.c

@@ -141,12 +141,11 @@ __libc_main (long _argc, char **_argv, char **_envp)
 	else if (_rootdir < 'a' || _rootdir > 'z')
 		_rootdir = 0;
 
-	/* if we're running under MiNT, and the current drive is U:, then this
+	/* if we're running under MiNT, and the drive U: exists, then this
 	 * must be our preferred drive
 	 */
-	if (!_rootdir && __mint >= 9) {
-		if (Dgetdrv() == 'U'-'A')
-			_rootdir = 'u';
+	if (!_rootdir && (Drvmap() & (1L << ('U'-'A')))) {
+		_rootdir = 'u';
 	}
 
 	/* If running under some recent MiNT there is no reason to convert 

unix/open.c

@@ -54,29 +54,28 @@ failsafe_Fopen (const char* name, int flags)
 }
 
 int
-__open_v (const char *_filename, int iomode, va_list argp)
+__open_v (const char *filename, int iomode, va_list argp)
 {
 	int rv;
 	int modemask;			/* which bits get passed to the OS? */
 	char filenamebuf[PATH_MAX];
 	long fcbuf;			/* a temporary buffer for Fcntl */
 	struct stat sb;
 	unsigned int pmode = 0;
-	char *filename = (char *) _filename;
 
-	if (!_filename) {
+	if (!filename) {
 		__set_errno (EFAULT);
 	    	return -1;
 	}
 
-	if (*_filename == '\0') {
+	if (*filename == '\0') {
 		__set_errno (ENOENT);
 		return -1;
 	}
 
 	if (!__libc_unix_names) {
+	    	_unx2dos(filename, filenamebuf, sizeof (filenamebuf));
 	    	filename = filenamebuf;
-	    	_unx2dos(_filename, filename, sizeof (filenamebuf));
 	}
 
 	if (iomode & O_CREAT)