shaderc: Added SPIR-V target.
shaderc: Added SPIR-V target.

mendsley/bgfx,MikePopoloski/bgfx,fluffyfreak/bgfx,attilaz/bgfx,LWJGL-CI/bgfx,jpcy/bgfx,bkaradzic/bgfx,fluffyfreak/bgfx,MikePopoloski/bgfx,mmicko/bgfx,jpcy/bgfx,attilaz/bgfx,septag/bgfx,mendsley/bgfx,LWJGL-CI/bgfx,septag/bgfx,jpcy/bgfx,bkaradzic/bgfx,fluffyfreak/bgfx,fluffyfreak/bgfx,Synxis/bgfx,Synxis/bgfx,emoon/bgfx,emoon/bgfx,LWJGL-CI/bgfx,bkaradzic/bgfx,emoon/bgfx,jdryg/bgfx,jdryg/bgfx,LWJGL-CI/bgfx,mmicko/bgfx,mendsley/bgfx,MikePopoloski/bgfx,Synxis/bgfx,jdryg/bgfx,jdryg/bgfx,septag/bgfx,jpcy/bgfx,attilaz/bgfx,bkaradzic/bgfx,mmicko/bgfx