[XML] Fix profile-specific definitions for EXT_texture_sRGB enums

[castholm]

b28b214 (PR: #662; issue: #656; CC: @zmike, @oddhack) introduced api="glcore" on <require> elements. This broke my code generator when I recently tried to update it to the latest gl.xml.

I tried to update my processing of gl.xml, but the problem is that using api="gl" and api="glcore" the way b28b214 did is fundamentally incompatible with how extensions have been defined in the past.

In other extensions, <require api="gl"> matches both the Compatibility and Core profiles. profile="compatibility" is used to further specify features that are exclusive to Compatibility. glcore is only ever used for <extension supported="gl|glcore">, never for anything else. For example:

<extension name="GL_ARB_vertex_type_2_10_10_10_rev" supported="gl|glcore">
    <require>
        <enum name="GL_UNSIGNED_INT_2_10_10_10_REV"/>
        <enum name="GL_INT_2_10_10_10_REV"/>
        <command name="glVertexAttribP1ui"/>
        <command name="glVertexAttribP1uiv"/>
        <command name="glVertexAttribP2ui"/>
        <command name="glVertexAttribP2uiv"/>
        <command name="glVertexAttribP3ui"/>
        <command name="glVertexAttribP3uiv"/>
        <command name="glVertexAttribP4ui"/>
        <command name="glVertexAttribP4uiv"/>
    </require>
    <require api="gl" profile="compatibility">
        <command name="glVertexP2ui"/>
        <command name="glVertexP2uiv"/>
        <command name="glVertexP3ui"/>
        <command name="glVertexP3uiv"/>
        <command name="glVertexP4ui"/>
        <command name="glVertexP4uiv"/>
        <command name="glTexCoordP1ui"/>
        <command name="glTexCoordP1uiv"/>
        <command name="glTexCoordP2ui"/>
        <command name="glTexCoordP2uiv"/>
        <command name="glTexCoordP3ui"/>
        <command name="glTexCoordP3uiv"/>
        <command name="glTexCoordP4ui"/>
        <command name="glTexCoordP4uiv"/>
        <command name="glMultiTexCoordP1ui"/>
        <command name="glMultiTexCoordP1uiv"/>
        <command name="glMultiTexCoordP2ui"/>
        <command name="glMultiTexCoordP2uiv"/>
        <command name="glMultiTexCoordP3ui"/>
        <command name="glMultiTexCoordP3uiv"/>
        <command name="glMultiTexCoordP4ui"/>
        <command name="glMultiTexCoordP4uiv"/>
        <command name="glNormalP3ui"/>
        <command name="glNormalP3uiv"/>
        <command name="glColorP3ui"/>
        <command name="glColorP3uiv"/>
        <command name="glColorP4ui"/>
        <command name="glColorP4uiv"/>
        <command name="glSecondaryColorP3ui"/>
        <command name="glSecondaryColorP3uiv"/>
    </require>
</extension>

But b28b214 takes <require api="gl"> to mean "Compatibility only" and <require api="glcore"> to mean "Core only". This inconsistency makes it impossible to process gl.xml fully automatically.

This PR rewrites the definitions for EXT_texture_sRGB to use profile="compatibility" for the luminance enums.

[NogginBops]

We've also had issues with this change in our generator. This seems like the more consistent way to handle this.

[zmike]

Seems fine to me. @oddhack up to you