*Add harfbuzz include dir. Set preferred OpenGL provider to GLVND

[loathingKernel]

Harfbuzz is required due to newer Pango versions not linking automatically to it.

OpenGL preference silences a warning during configure and forces linking to vendor agnostic GLVND. Should be transparent to pcsxr itself.

[perdolka]

No updates since February.
Looks like @iCatButler stopped supporting the pcsxr?

[loathingKernel]

@perdolka How is that relevant to this PR?
When they are available again, they can merge it.

[johnny-mac]

Its been 30 days and no sign of Icatbutler... perhaps we should fork this project and apply this PR?
I'm here because harfbuzz hb.h errors, looking for a solution.

[loathingKernel]

You can always clone from my fork or apply the patches from these PRs by applying .patch at the end of the URL. I don't think we need yet another fork, most probably it will just result in yet another "unmaintained" fork. I put that in quotes because this repo is not a continuation of general work on PCSXR but rather a repo where @iCatButler put his work on scratching his own itches with PGXP.

[quequotion]

I found these changes in a patch for pcsxr-pgxp-git (AUR package).

They work!