This makes the EGL interface select OpenGL|ES contexts over "desktop"
OpenGL ones.
Possibly not useful for anyone outside my own debugging, but you never
know
The spec says it should have an EXT not OES suffix, as it's enabled as
an interaction with GL_EXT_multi_draw_arrays.
On some drivers GetProcAddress() returns NULL, which causes the
GLExtensions init to fail
This 'happened' to work if GetProcAddress() doesn't return NULL on missing
functions (as allowed in EGL) - as the function appears to never be called so
this would not have been noticed.
Mesa also (incorrectly?) exports the EXT version, so this would all
happen to work there, but appears to be contrary to the spec.
This invalid prefix even ended up in the upstream khronos registry, the
issue was reported here:
https://github.com/KhronosGroup/OpenGL-Registry/issues/81
struct GekkoOPTemplate was implemented differently in different
compilation units, which breaks the ODR and could end up causing issues
as symbols exported from one compilation unit could end up being used by
another even if they have different implementations.
This puts them in an anonymous namespace, restricting any generated
symbols to the single compilation unit.