Re: ./configure libgfx

[Ralf Wildenhues]

Hello Miriam,

Thanks for the report.

* address@hidden wrote on Mon, Nov 20, 2006 at 12:03:19PM CET:
> 
> I send you this output, and the configure.log, for your convenience as
> it's specified on it.
> 
> checking GL/glext.h usability... no
> checking GL/glext.h presence... yes
> configure: WARNING: GL/glext.h: present but cannot be compiled
> configure: WARNING: GL/glext.h: check for missing prerequisite headers?
> configure: WARNING: GL/glext.h: proceeding with the preprocessor's result

> configure: WARNING: GL/glxext.h: present but cannot be compiled
> configure: WARNING: GL/glxext.h: check for missing prerequisite headers?
> configure: WARNING: GL/glxext.h: proceeding with the preprocessor's result

This is a problem in the libgfx package.  The general description of the
problem can be found here:
http://www.gnu.org/software/autoconf/manual/html_node/Present-But-Cannot-Be-Compiled.html

More specifically, the package does something like
  AC_CHECK_HEADERS([GL/glext.h GL/glxext.h])

which is wrong, because it fails to list prerequisite headers.
Something like this is better:

AC_CHECK_HEADERS([X11/X.h GL/gl.h])
AC_CHECK_HEADERS([GL/glx.h GL/glext.h GL/glxext.h], [], [],
  [[#ifdef HAVE_X11_X_H
    #  include <X11/X.h>
    #endif
    #ifdef HAVE_GL_GL_H
    #  include <GL/gl.h>
    #endif
    #ifdef HAVE_GL_GLX_H
    #  include <GL/glx.h>
    #endif
  ]])

But really I have not too much experience with X and GL, so please take
the advice with a grain of salt, report this to the maintainer of the
package, so they can look up the exact list of needed headers, and fix
the package's configure.ac script.

Also it may be helpful to know that Autoconf 2.61 is the current
version; 2.57 is quite old.

Cheers,
Ralf