A segfault in xbps-create(1) was found in:
https://github.com/void-linux/void-packages/pull/7524
xbps-create adds a file type string to the xentry for every file it
finds in `destdir`, files other than symlinks, regular files and
directories weren't handled and resulted in a segfault later when
when processing the xentry structures.
This commit adds checks for sockets and fifos and exits with an
appropriate error message or with a generic error message for every
other unhandled file.
Closes#66
a46be6867a