   strange extension warning...
  In order to teach myself more about OpenGL extensions, I decided to rewrite my particle engine using GL_NV_point_sprite.  It worked fine, and I decided to try and use glPointParameterfvARB to make the sprite sizes vary with distance.  I''m using Linux, so I used glx to get a pointer to the function like so:PFNGLPOINTPARAMETERFVARBPROC glPointParameterfvARB = NULL;glPointParameterfvARB = (PFNGLPOINTPARAMETERFVARBPROC)    glXGetProcAddressARB((const GLubyte*)"glPointParameterfvARB");  I seem to able to use the function OK, but I get this warning:/usr/bin/ld: Warning: type of symbol `glPointParameterfvARB'' changed from 2 to 1 in /tmp/ccMZQR65.o  Could someone please tell me how to get rid of this warning? 
  turn compiler warnings off, if your compiler has this option. 