Formerly we relied on static linkage. However, in the presense of modern
OpenGL (ES) implementations it is not easily identifable which library to link
against. For example, on Linux amd64 with nVidia drivers and SDL2 setup to
create a GLES 1.1 context one would need to link against libGL.so. However,
traditionally GLES 1.1 required to link against libGLESv1_CM.so. To prevent a
huge mess we simply resolve the OpenGL functions on run-time now and stop
linking against a static library (in most cases).
GLES support needs to be enabled manually on configure time for now.
Tizen changes have NOT been tested.
There might be various error flags and we need to clear all of them to get
precise error results. Thus, we need to call glGetError in a loop to achieve
that.
