The current make-null-gl-array fails to run as currently defined. When called with (gl:make-null-gl-array :unsigned-short), SBCL gives the following error:
0 fell through CTYPECASE expression.
Wanted one of (SYMBOL FUNCTION).
[Condition of type SB-KERNEL:CASE-FAILURE]
The problem seems simply to be that the arguments when calling MAKE-GL-ARRAY-FROM-POINTER are reversed.
Specifically, instead of
(make-gl-array-from-pointer (null-pointer) 0 type)
the body of MAKE-NULL-GL-ARRAY should be
(make-gl-array-from-pointer (null-pointer) type 0)