AC_SEARCH_LIBS([glBegin], [GL],,
[AC_MSG_ERROR([libGL is required])])
+AC_SEARCH_LIBS([gluPerspective], [GLU],,
+ [AC_MSG_ERROR([libGLU is required])])
+
AC_SEARCH_LIBS([clock_gettime], [rt],
[AC_DEFINE([HAVE_CLOCK_GETTIME], 1,
[Define to 1 if you have the 'clock_gettime' function.])])