Fix for missing gl function on Windows

Author: ivansafrin

Core/Contents/Source/PolyGLRenderer.cpp

@@ -57,6 +57,7 @@ PFNGLGETBUFFERPOINTERVARBPROC glGetBufferPointervARB;
 
 PFNGLVERTEXATTRIBPOINTERPROC glVertexAttribPointer;
 PFNGLENABLEVERTEXATTRIBARRAYARBPROC glEnableVertexAttribArrayARB;
+PFNGLDISABLEVERTEXATTRIBARRAYARBPROC glDisableVertexAttribArrayARB;
 PFNGLBINDATTRIBLOCATIONPROC glBindAttribLocation;
 
 PFNGLGETPROGRAMIVPROC glGetProgramiv;