Implement glGetPointerv().

Bug 26794307

Change-Id: I0aa175f091550d544a33503b602c191353e7a1c5
Reviewed-on: https://swiftshader-review.googlesource.com/4606
Tested-by: Nicolas Capens <capn@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
3 files changed