if sqrtf() isn't available.  This is 'way better than using -Dtanf=tan etc. in Makefile.

Just leave Steve Marx's insistence on FLTK >=1.1.x.
Check for values.h.
If we seem to be running on MacOS X, add more special tests:
   Search -lmx for sqrtf() etc., rather than a bunch of -D'efines for float functions.
	If they (or at least sqrtf) are not present, geometry.h now #define's em.
   Insist on {fltkdir}/FL/mac.r so we can use Rez to tag partiview as a GUI app,
	otherwise it can never get keyboard/mouse focus.

needed on MacOS X.

Need config.h early.
Initialize "oldopengl".
More digits for "where".

nobody else has heard of it.

to stop animation.

Put alloca stuff before all other includes.

Make sure to AC_CHECK_HEADERS after CC and CPP are defined.
Use autoconf 2.52.  2.13 doesn't guess CC correctly on mingw32.

and also seem to require an additional file, config.sub.
Who needs em.

attributes 0 1 2 ...  even though they aren't stored that way.

focalpoint feature.
warp in N-to-3D projection mode.
draw points using vertex arrays if available.
lum <var> {abs <base> | lin}

Use warp_invalidate() when conditions change.

Allow dyndata processors to switch themselves off with st->dyn.enabled = -1.