configure: WARNING: GL/glx.h: present but cannot be compiled
configure: WARNING: GL/glx.h: check for missing prerequisite headers?
configure: WARNING: GL/glx.h: see the Autoconf documentation
configure: WARNING: GL/glx.h: section "Present But Cannot Be Compiled"
configure: WARNING: GL/glx.h: proceeding with the preprocessor's result
configure: WARNING: GL/glx.h: in the future, the compiler will take precedence
configure: WARNING: ## -------------------------------------- ##
configure: WARNING: ## Report this to gtkglext-list@gnome.org ##
configure: WARNING: ## -------------------------------------- ##