Missing glBlend*ARB functions

[norru]

I'm using epoxy as the Gl loader for https://github.com/itadinanta/gfx-gtk.

gfx-rs attempts to load the following functions and fails:

glBlendEquationSeparateiARB
glBlendEquationiARB
glBlendFuncSeparateiARB
glBlendFunciARB

as a workaround I'm mapping them to their non-ARB counterparts as follows

pub fn epoxy_get_proc_addr(s: &str) -> *const std::ffi::c_void {
	// Workaround for missing functions in gfx-rs
	let s = match s {
		"glBlendEquationSeparateiARB" => "glBlendEquationSeparatei",
		"glBlendEquationiARB" => "glBlendEquationi",
		"glBlendFuncSeparateiARB" => "glBlendFuncSeparatei",
		"glBlendFunciARB" => "glBlendFunci",

		_ => s,
	};

	let v = epoxy::get_proc_addr(s);
	if v.is_null() {
		println!("Function {} is missing {:?}", s, v);
	}
	v
}

I have not seen an adverse effect yet but this is likely to bite me in the backside at some point if left untreated.

[norru]

Hi, I've got a simple one-liner fix for this, will submit PR shortly.