Discussion: Add TARGET_GLES_2 define?

[bakercp]

@arturoc (et al.) I'm wondering if we should consider adding a TARGET_GLES_2 define in addition to our TARGET_GLES define. This may be a larger issue associated with the fixed vs. programable GL pipeline (not just GLES). Anyway, thoughts?

[arturoc]

yes i think we would need something similar but not at the same level as TARGET_OPENGLES but additionally, something like OF_USING_GLES1 and OF_USING_GLES2 so we can link conditionally with one of the implementations only or with both. that way things that are common don't need to be ifdef for both, only for TARGET_OPENGLES

right now we need to link with both libraries which doesn't seem very correct (in pandaboard you even need to do this trick of changing the linking order which feels super hacky) and will probably break in some platforms

also having everything included it can be confusing to know what you can use and what not depending on which version of GL you are using since it will compile but not work