x11: Clear window after initialization.
x11: Clear window after initialization.

v3n/bgfx,jdryg/bgfx,Extrawurst/bgfx,ming4883/bgfx,elmindreda/bgfx,BlueCrystalLabs/bgfx,aonorin/bgfx,LWJGL-CI/bgfx,marco-we/bgfx,attilaz/bgfx,ktotheoz/bgfx,0-wiz-0/bgfx,jpcy/bgfx,Synxis/bgfx,Vertexwahn/bgfx,emoon/bgfx,darkimage/bgfx,cuavas/bgfx,cyndis/bgfx,janstk/bgfx,attilaz/bgfx,jpcy/bgfx,emoon/bgfx,janstk/bgfx,Vertexwahn/bgfx,sergeScherbakov/bgfx,kondrak/bgfx,Vertexwahn/bgfx,ocornut/bgfx,jpcy/bgfx,jpcy/bgfx,janstk/bgfx,mmicko/bgfx,elmindreda/bgfx,ming4883/bgfx,aonorin/bgfx,MikePopoloski/bgfx,mcanthony/bgfx,andr3wmac/bgfx,jdryg/bgfx,mcanthony/bgfx,ocornut/bgfx,cuavas/bgfx,Extrawurst/bgfx,bkaradzic/bgfx,Extrawurst/bgfx,LSBOSS/bgfx,cuavas/bgfx,ktotheoz/bgfx,LWJGL-CI/bgfx,mendsley/bgfx,mendsley/bgfx,sergeScherbakov/bgfx,emoon/bgfx,MikePopoloski/bgfx,andr3wmac/bgfx,aonorin/bgfx,0-wiz-0/bgfx,v3n/bgfx,darkimage/bgfx,jdryg/bgfx,kondrak/bgfx,marco-we/bgfx,darkimage/bgfx,mcanthony/bgfx,elmindreda/bgfx,LWJGL-CI/bgfx,fluffyfreak/bgfx,mmicko/bgfx,septag/bgfx,bkaradzic/bgfx,sergeScherbakov/bgfx,mendsley/bgfx,septag/bgfx,bkaradzic/bgfx,ocornut/bgfx,LWJGL-CI/bgfx,v3n/bgfx,0-wiz-0/bgfx,mmicko/bgfx,fluffyfreak/bgfx,septag/bgfx,cyndis/bgfx,bkaradzic/bgfx,ming4883/bgfx,MikePopoloski/bgfx,jdryg/bgfx,kondrak/bgfx,ktotheoz/bgfx,BlueCrystalLabs/bgfx,Synxis/bgfx,LSBOSS/bgfx,attilaz/bgfx,marco-we/bgfx,LSBOSS/bgfx,andr3wmac/bgfx,fluffyfreak/bgfx,Synxis/bgfx,BlueCrystalLabs/bgfx,cyndis/bgfx,fluffyfreak/bgfx