respect old versions of glx.h a little better

panda/src/glxdisplay/glxGraphicsPipe.h

@@ -55,7 +55,6 @@ typedef int XIC;
 #if !defined(HAVE_GLXFBCONFIG) && defined(GLX_SGIX_fbconfig) && defined(GLX_SGIX_pbuffer)
   // If the system glx version isn't 1.3, but these were defined as
   // extensions, we can work with that.
-  #define GLX_RGBA_TYPE GLX_RGBA_TYPE_SGIX
   #define GLXFBConfig GLXFBConfigSGIX
   #define GLXPbuffer GLXPbufferSGIX
   #define glXChooseFBConfig glXChooseFBConfigSGIX

panda/src/glxdisplay/glxext.h

@@ -332,6 +332,7 @@ typedef struct {
      the following to compile. */
 typedef struct __GLXFBConfigRec *GLXFBConfig;    
 typedef XID GLXPbuffer;
+typedef XID GLXWindow;
 
 #ifdef GLX_GLXEXT_PROTOTYPES
 extern GLXFBConfig * glXGetFBConfigs (Display *, int, int *);