Re: AC_CHECK_HEADER, autoconf 2.57, includes problem

[Tim Van Holder]

On Wed, 2003-01-22 at 15:01, Bill Schottstaedt wrote:
> My apologies if this has already been reported.

Similar things have been reported, so this _might_ be fixed in CVS
autoconf already.

> In autoconf 2.57 in AC_CHECK_HEADER, I think the gcc -E conftest
> check for header usability needs to include the default includes
> from the header presence test.  In my case,
> 
>         OLD_CFLAGS="$CFLAGS"
>         CFLAGS="-I/usr/local/include/gtkglext-1.0 
> -I/usr/local/lib/gtkglext-1.0/include $GTK_CFLAGS $CFLAGS"

Shouldn't you add the -I flags to CPPFLAGS, as those are precompiler
options? My guess is that this may fix the problem as well (assuming
the precompiler test run by configure uses $CPPFLAGS).
I'd certainly agree that it would be nice if configure tried to grok
CFLAGS and extract the options that could/should go into CPPFLAGS, but
I expect this would be quite error-prone.
At the very least, the docs for AC_CHECK_HEADER should probably be
expanded to mention this.

>       AC_CHECK_HEADER(gtk/gtkgl.h,
>         [
>             GL_LIBS="$GL_LIBS -lgdkglext-x11-1.0 -lgtkglext-x11-1.0"
>             GL_FLAGS="$GL_FLAGS -I/usr/local/include/gtkglext-1.0 
> -I/usr/local/lib/gtkglext-1.0/include"
>         ],
>         [
>             GL_LIBS="$GL_LIBS -lgdkglext-x11-0.x -lgtkglext-x11-0.x"
>             GL_FLAGS="$GL_FLAGS -I/usr/local/include/gtkglext-0.x"
>         ])
>       CFLAGS="$OLD_CFLAGS"
> 
> (yes I know it's ugly -- there's no config program for this library, so
> I have to search for it by hand).  This gets:

-- 
Tim Van Holder <address@hidden>