Commit Briefs
refactor the makefile / configure
steal more (good) stuff from mandoc-portable :)
fix getprogname shim
HAVE_PROGRAM_INVOCATION_SHORT_NAME is always defined; look at wether it's zero or not.
add proper copyrights
was a mistake on my part and a leftover from the first iterations. Initially I only stole a few bits, that's why the comment but not the copyright, but then i threwed out and restarted using oconfigure. Then the configure script has its own independent changes, but need to give attribution nevertheless.