Fixed bug introduced by calling do_open() for O_RDONLY files. Changed it

so the check for dry_run and CHECK_RO are not done when flags is O_RDONLY.
Only do the adding of O_BINARY, which was the intention.

syscall.c

@@ -76,12 +76,14 @@ int do_rmdir(char *pathname)
 
 int do_open(char *pathname, int flags, mode_t mode)
 {
-	if (dry_run) return -1;
+	if (flags != O_RDONLY) {
+	    if (dry_run) return -1;
+	    CHECK_RO
+	}
 #ifdef O_BINARY
 	/* for Windows */
 	flags |= O_BINARY;
 #endif
-	CHECK_RO
 	return open(pathname, flags, mode);
 }