Fix the GL_MAX_VERTEX_UNITS_ARB undeclared compilation error.

dlls/d3d8/d3dcore_gl.h

@@ -41,6 +41,52 @@
  *  defines and functions pointer
  */
 
+/* GL_ARB_vertex_blend */
+#ifndef GL_ARB_vertex_blend
+#define GL_ARB_vertex_blend 1
+#define GL_MAX_VERTEX_UNITS_ARB           0x86A4
+#define GL_ACTIVE_VERTEX_UNITS_ARB        0x86A5
+#define GL_WEIGHT_SUM_UNITY_ARB           0x86A6
+#define GL_VERTEX_BLEND_ARB               0x86A7
+#define GL_CURRENT_WEIGHT_ARB             0x86A8
+#define GL_WEIGHT_ARRAY_TYPE_ARB          0x86A9
+#define GL_WEIGHT_ARRAY_STRIDE_ARB        0x86AA
+#define GL_WEIGHT_ARRAY_SIZE_ARB          0x86AB
+#define GL_WEIGHT_ARRAY_POINTER_ARB       0x86AC
+#define GL_WEIGHT_ARRAY_ARB               0x86AD
+#define GL_MODELVIEW0_ARB                 0x1700
+#define GL_MODELVIEW1_ARB                 0x850A
+#define GL_MODELVIEW2_ARB                 0x8722
+#define GL_MODELVIEW3_ARB                 0x8723
+#define GL_MODELVIEW4_ARB                 0x8724
+#define GL_MODELVIEW5_ARB                 0x8725
+#define GL_MODELVIEW6_ARB                 0x8726
+#define GL_MODELVIEW7_ARB                 0x8727
+#define GL_MODELVIEW8_ARB                 0x8728
+#define GL_MODELVIEW9_ARB                 0x8729
+#define GL_MODELVIEW10_ARB                0x872A
+#define GL_MODELVIEW11_ARB                0x872B
+#define GL_MODELVIEW12_ARB                0x872C
+#define GL_MODELVIEW13_ARB                0x872D
+#define GL_MODELVIEW14_ARB                0x872E
+#define GL_MODELVIEW15_ARB                0x872F
+#define GL_MODELVIEW16_ARB                0x8730
+#define GL_MODELVIEW17_ARB                0x8731
+#define GL_MODELVIEW18_ARB                0x8732
+#define GL_MODELVIEW19_ARB                0x8733
+#define GL_MODELVIEW20_ARB                0x8734
+#define GL_MODELVIEW21_ARB                0x8735
+#define GL_MODELVIEW22_ARB                0x8736
+#define GL_MODELVIEW23_ARB                0x8737
+#define GL_MODELVIEW24_ARB                0x8738
+#define GL_MODELVIEW25_ARB                0x8739
+#define GL_MODELVIEW26_ARB                0x873A
+#define GL_MODELVIEW27_ARB                0x873B
+#define GL_MODELVIEW28_ARB                0x873C
+#define GL_MODELVIEW29_ARB                0x873D
+#define GL_MODELVIEW30_ARB                0x873E
+#define GL_MODELVIEW31_ARB                0x873F
+#endif
 /* GL_EXT_secondary_color */
 #ifndef GL_EXT_secondary_color
 #define GL_EXT_secondary_color 1