merged the getopt and mlock patches

I merged the getopt_long patch and the mlock patches (since they modified the same code).

I cleaned up the patch a bit. It now is enabled via the configure script with the --enable-mlock flag, the flag is now -m/--mlock (instead of -l/--lock).

The configure script also now checks for the presence of mlockall, and checks that glibc is >= 2.5 (the version the mlockall bug was fixed), and disables the mlockall if it is not met. It does the same for getopt_long and the use of getopt.

I also added documentation for --mlock to the manpage.

I renamed --opendisplay to --open-display (opendisplay is improper english). The documentation does not mention it, but --opendisplay will still work for backward compatibility.

Note that for the manpages, I updated the rxvtd.1.pod file, so the rxvtd.1.man.in file will need to be regenerated.

The new patch is here

Edit: It was merged upstream... it should be available when you --enable-frills in the next release.