Re: could not setup config headers machinery

[Ralf Wildenhues]

Hello David,

* Dr. David Kirkby wrote on Tue, Oct 12, 2010 at 09:53:46PM CEST:
> I'm trying to sort out why the latest version of the GNU Scientific Library 
> (GSL)

> does not build properly on some AIX systems (the developers are aware of it).
> 
> I need to check if 'fprnd_t' is defined in float.h or not.
> 
> Is there any particular trick needed to check for things in float.h?

> The *only* change I've made is this single line in configure.ac
> 
> AC_CHECK_DECLS([fprnd_t],[],[],[[#include <float.h>]])
> 
> But after running will always cause the generated configure script
> to fail to execute properly - see below. Notice it does not find
> 'fprnd_t', (on the second line) but then later generates an error.
[...]

Can you send 'diff -u' of the two configure files (without above line
and with)?  Of even of the one with float.h and the one with math.h?

> Conversely, if I change it to
> 
> AC_CHECK_DECLS([fprnd_t],[],[],[[#include <math.h>]])
> 
> then the configure script works. But checking in math.h is not a lot
> of use when I want to check in float.h

If that line really is the cause of the issues you're seeing (rather
than some other circumstance), then the diff should provide a strong
hint.

Thanks,
Ralf