Julien Isorce authored May 27, 2015 and Tim-Philipp Müller committed Dec 09, 2017

Previously when compiling GstGL with both GL and GLES2,
GL_RGBA8 was picked from GL/gl.h. But a clash may happen at
runtime when one is selecting GLES2.

gst_gl_internal_format_rgba allows to check at runtime
if it should use GL_RGBA or GL_RGBA8.