fix some pointer signedness issues (this was invalid C)
[musl] / src / fcntl /
drwxr-xr-x   ..
-rw-r--r-- 158 creat.c
-rw-r--r-- 402 fcntl.c
-rw-r--r-- 349 open.c
-rw-r--r-- 390 openat.c