Upstream patch from pkgsrc that fixes build on NetBSD >= 3

Source:

http://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/devel/p5-Proc-ProcessTable/patches/patch-aa
NetBSD prefixes 'perl: ' to process cmdline, make bugfix-51470_cmndline_mod20_error.t more forgiving.
Merge pull request #1 from bingos/master

Resolving two issues on NetBSD, compiles on NetBSD again.