Fixed OpenGL issues noticed on mingw intel/nvidia
Fixed OpenGL issues noticed on mingw intel/nvidia

YosysHQ/nextpnr,SymbiFlow/nextpnr,YosysHQ/nextpnr,YosysHQ/nextpnr,SymbiFlow/nextpnr,SymbiFlow/nextpnr,SymbiFlow/nextpnr,YosysHQ/nextpnr