Fix blend func state save/restore
Fix blend func state save/restore

AFAIK there's no such enum as `GL_BLEND_SRC` or `GL_BLEND_DST` in OpenGL3 and OpenGL4.

Maybe they're left over from previous versions? They don't even seem to exist in OpenGL 2.1. In fact checking they were deprecated in OpenGL 1.5 (they exist in 1.3)

elect86/imgui,Pagghiu/imgui,ocornut/imgui,Flix01/imgui,Pagghiu/imgui,nProtect/imgui,cmaughan/imgui,cmaughan/imgui,nProtect/imgui,mikesart/imgui,Flix01/imgui,Flix01/imgui,cmaughan/imgui,tom-seddon/imgui,ocornut/imgui,cmaughan/imgui,mikesart/imgui,ggtucker/imgui,burningreggae/imgui,thevaber/imgui,bkaradzic/imgui,bkaradzic/imgui,wflohry/imgui-addons,dougbinks/imgui,tom-seddon/imgui,wflohry/imgui-addons,aimotive/imgui-glfw,ggtucker/imgui,burningreggae/imgui,ocornut/imgui,elect86/imgui,aimotive/imgui-glfw,bkaradzic/imgui,thevaber/imgui,nProtect/imgui,ggtucker/imgui,dougbinks/imgui