What is necessary to detect OpenGL

Hello. I am currently trying to build SDL 1.2.15, and during the configure stage, it is not able to detect the presence of Opengl. I created a symbolic link from the folder where are the OpenGL headers, called “GL”, to /usr/local/include. There, by some reason the files inside the “GL” folder where actually copied, instead of being created symlinks to them. Anyway, nowinside the GL folder on /usr/local/include, there is:
gl.h, glext.h, glu.h glu_mangle.h and glx.h

I can run OGL applications, so the libraries themselves should be ok.

So I have no idea way the detection process of configure cannot find them. Perhaps someone could help me to understand how configure tries to detect the presence of OpenGL? Thanks for the support.

For SDL 1.2 on Unix, it tries to compile a C program that looks like this:

#include <GL/gl.h>
#include <GL/glx.h>
#include <GL/glu.h>

…and that’s it.

You should look at config.log, search for the string “OpenGL” and see if this failed in any obvious way around that area.