chunk 1:
avoid hardcoding nas paths; pkgsrc installs it somewhere else.
This part could probably be done better.

chunk 2:
-L/usr/lib is unnecessary

chunk 3:
Better DragonFly support.

--HG--
branch : SDL-1.2
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/branches/SDL-1.2%402452