GLES3: Try to re-enable PSP-based mipmapping generation
Set amask based on ReplaceAlphaWithStencil()
Regroup Stencil Testing
ReplaceAlphaWithStencil() has been checked for gstate.isStencilTestEnabled()
Prevent replacing an acosf variant.

There's another func that looks identical to this one except its jal in
VC2.  Replacing it with acosf() breaks fog and targetting.
Save/restore local file handles and seek positions
Merge pull request #4933 from KentuckyCompass/savestate_openfiles

Save/restore local file handles and seek positions
Merge pull request #4898 from raven02/patch-21

GLES3: enable PSP-based mipmapping generation
Merge pull request #4913 from raven02/patch-25

Set alpha mask based on ReplaceAlphaWithStencil()
Don't declare fragColor0 unless we will use it. See #4877
Shaders: Make sure to always use matching versions.

Really should unify this somehow.
Fix #4913
Merge pull request #4934 from raven02/patch-28

Fix pull request #4913
Ignore the material update flag w/o vertex color.

Instead of using materialambient for all of them.

Fixes #3918, and seems to match tests with 3dstudio.
Fix typesafety (ScreenCoords not DrawingCoords.)
softgpu: Use region for debugger buffer previews.

It's fine if it resizes or etc., but this should generally be the
interesting area of vram to show, without any confusing noise on the
side/etc.
softgpu: Implement vertex preview.

And move ConvertMatrix4x3To4x4() into a common place since there were
differing implementations, which was only confusing.
softgpu: Fix preview region y1 in ge debugger.
Merge pull request #4937 from unknownbrackets/gpu-minor

Ignore material update when no vertex color, softgpu vertex preview
Avoid reseved identifiers like _SP, etc.

R_SP is not that bad.