- recognise PNG files and set appropriate mime type (from FreeBSD).
- remove botched mkstemp() conversion which broke mpack(1);
a proper mkstemp conversion is intrusive.
- use some additional XXXX in the temporary filename.
- let this build with CLang scan-build.
* Fix buffer overflow. (Obtained from Debian)
* Strip leading "../" when creating new files. (Obtained from Debian)
Clean-up by yours truly:
* Parameter parsing fix. (Obtained from Debian)
* Prefer native getopt() and MD5 functions over the included ones.
* Make munpack synopsis agree with actual parameters.
* Respect CC.