Simplify reading $LDFLAGS
Allow user to suppress install target
Add support for DESTDIR installs
Add support for linking under an alternate name
Convert thief-steal messages to use weapon name macros
Fold headlight message into powerup_basic
Make Boss_dying an int

It is read and written as one, so store it as one.
Remove unnecessary exit(1) calls in physfsx

Error never returns, so calling exit afterward is pointless.
Make ranking strings const
Mark reticle control data const
Refactor PCX loading code to simplify exit path
Use a static wrapper in PCX reading code
Adjust alignment of vulcan/gauss ammo display
Mark weapon related globals as const
Mark powerup_basic as printf-like
Treat robot joints as const