This is an extremely extensive patch as it hits every cvar, and every
usage of the cvars. Cvars no longer store the value they control,
instead, they use a cexpr value object to reference the value and
specify the value's type (currently, a null type is used for strings).
Non-string cvars are passed through cexpr, allowing expressions in the
cvars' settings. Also, cvars have returned to an enhanced version of the
original (id quake) registration scheme.
As a minor benefit, relevant code having direct access to the
cvar-controlled variables is probably a slight optimization as it
removed a pointer dereference, and the variables can be located for data
locality.
The static cvar descriptors are made private as an additional safety
layer, though there's nothing stopping external modification via
Cvar_FindVar (which is needed for adding listeners).
While not used yet (partly due to working out the design), cvars can
have a validation function.
Registering a cvar allows a primary listener (and its data) to be
specified: it will always be called first when the cvar is modified. The
combination of proper listeners and direct access to the controlled
variable greatly simplifies the more complex cvar interactions as much
less null checking is required, and there's no need for one cvar's
callback to call another's.
nq-x11 is known to work at least well enough for the demos. More testing
will come.
Finally. I never liked it (felt bad adding it in the first place), and
it has caused confusion with function and global variable names, but it
did let me get the render plugins working.
Where possible, symbols have been made static, prefixed with gl_/GL_ or
moved into the code shared by all renderers. This will make doing plugins
easier but done now for link testing.
The major change is that we no longer require libGL to even exist on the
system at compile time for the GL targets, we dynamicly link to the
libGL of choice at run time. (This probably breaks most non-linux
systems, and all GL targets except -glx, some fixup will be needed.)
(This also kills glquake, dead dead DEAD! GONE FOREVER! WHEE!)
Some gl_draw cleanup.
Commented out equake alias model occlusion test stuff, very experimental.
Added the .lo and .la patterns to the .gitignore files.
Some minor sbar cleanup. (We don't use the disc in use symbol for
anything.)
