Comment 16 for bug 707794

For kdeedu, kalgebra also used GL (at least I think this is related):

In file included from /usr/include/GL/glu.h:38:0,
                 from ../../../kalgebra/src/graph3d.cpp:24:
/usr/include/GL/gl.h:168:17: error: conflicting declaration 'typedef double GLdouble'
/usr/include/qt4/QtOpenGL/qgl.h:74:17: error: 'GLdouble' has a previous declaration as 'typedef GLfloat GLdouble'
In file included from /usr/include/GL/gl.h:2091:0,
                 from /usr/include/GL/glu.h:38,
                 from ../../../kalgebra/src/graph3d.cpp:24:
/usr/include/GL/glext.h:5040:19: error: conflicting declaration 'typedef ptrdiff_t GLintptr'
/usr/include/GLES2/gl2.h:38:26: error: 'GLintptr' has a previous declaration as 'typedef khronos_intptr_t GLintptr'
/usr/include/GL/glext.h:5041:19: error: conflicting declaration 'typedef ptrdiff_t GLsizeiptr'
/usr/include/GLES2/gl2.h:39:26: error: 'GLsizeiptr' has a previous declaration as 'typedef khronos_ssize_t GLsizeiptr'