Small mingw compile fixes

Core/Contents/Include/PolyGLHeaders.h

@@ -98,6 +98,8 @@ typedef GLEEPFNGLBINDATTRIBLOCATIONPROC PFNGLBINDATTRIBLOCATIONPROC;
 typedef GLEEPFNGLUNIFORM2FPROC PFNGLUNIFORM2FPROC;
 typedef GLEEPFNWGLSWAPINTERVALEXTPROC PFNWGLSWAPINTERVALEXTPROC;
 typedef GLEEPFNWGLGETSWAPINTERVALEXTPROC PFNWGLGETSWAPINTERVALEXTPROC;
+typedef GLEEPFNGLGETPROGRAMIVPROC PFNGLGETPROGRAMIVPROC;
+typedef GLEEPFNGLGETACTIVEUNIFORMPROC PFNGLGETACTIVEUNIFORMPROC;
 #endif
 
 #if defined(__APPLE__) && defined(__MACH__)

Core/Contents/Source/PolyWinCore.cpp

@@ -38,7 +38,11 @@
 #include <Shellapi.h>
 #include <Commdlg.h>
 
-#if !defined(_MINGW)
+#if defined(_MINGW)
+#ifndef MAPVK_VSC_TO_VK_EX
+#define MAPVK_VSC_TO_VK_EX 3
+#endif
+#else
 PFNWGLSWAPINTERVALEXTPROC       wglSwapIntervalEXT = NULL;
 PFNWGLGETSWAPINTERVALEXTPROC    wglGetSwapIntervalEXT = NULL;
 #endif