Fixes for other compilers (#1912)

* remove invalid virtual keywords

* remove duplicate inline

* remove leading 0 in character literals

* add missing public keywords

* fix some struct/class mismatches

include/JSystem/J3DGraphBase/J3DVertex.h

@@ -7,8 +7,8 @@
 
 typedef struct _GXColor GXColor;
 class J3DModel;
-struct J3DAnmVtxColor;
-struct J3DVertexBuffer;
+class J3DAnmVtxColor;
+class J3DVertexBuffer;
 
 struct J3DVtxColorCalc {
     /* 8032E180 */ void calc(J3DModel*);