I think I need to come up with a better way of defining glsl builtins
and the strings are rather ugly (and I don't want to use qfcc system
header files).
iqm.vert now compiles, but doesn't pass validation yet (matrix bugs).
While I'm not happy with the module "creation" (at least it's limited to
two places), setting it up with spir-v capabilities and memory model
seems quite nice and should play nicely with being set up from within
source code, though using uint constant expressions might be overkill.
Attributes seem appropriate as GLSL's qualifiers affect variables rather
than types (since there's no typedef).
Not much is done with the attributes yet other than some basic error
checking (duplicates of non-layout attributes) and debug output, but
most (if not all) declarations get to the declaration code with
attributes intact.
The version directive really does only some error checking, and
only GL_EXT_multiview and GL_GOOGLE_include_directive are supported for
extensions, but enable/disable work (but not yet warn for multiview).
There's no direct support for namespaces in Ruamoko yet, nor even in
qfcc, but glsl's blocks bring in a bit of foundation for them, even the
concept of "using" (for blocks with no instance name).
The members don't get locations allocated to them yet, but
fstrianglest.vert compiles and links correctly otherwise.
Also, there's no error checking yet.
