Not sure how to regenerate the opemngl_ext.c file.
You need the extension registry CVS (you can find it here http://oss.sgi.com/projects/ogl-sample/ - no idea where the exact CVS informations are).
After, do 'make_opengl PATH_TO_EXTENSION_DIR 1.2' where PATH_TO_EXTENSION_DIR points to the '<OGL-SAMPLE-ROOT>/main/doc/registry/specs/' directory).
Anyway, if it can wait, it will be updated the next time I generate the file.
Lionel