Re: Bug report

[Lars Hecking]

Chris Schuit @ Euronet writes:
> configure: WARNING: net/if.h: present but cannot be compiled
> configure: WARNING: net/if.h: check for missing prerequisite headers?
> configure: WARNING: net/if.h: proceeding with the preprocessor's result
> configure: WARNING:     ## ------------------------------------ ##
> configure: WARNING:     ## Report this to address@hidden ##
> configure: WARNING:     ## ------------------------------------ ##
> checking for net/if.h... yes
> 
> Like this? :)

 It's not really an autoconf bug.

 AC_CHECK_HEADERS includes a default set of headers for compile tests, and
 a complete list is in the manual I think. These headers do not fulfil all
 prerequesites for all header files.

 The only cure at this stage is to test for the header in question separately.
 I can't say which prerequisite header is necessary for net/if.h, but
 config.log should tell you what to look for.

 Remove net/if.h from header checks, add the prerequisite header (I will use
 net/foo.h as an example here) to header checks, and then set up a separate
 test:

AC_CHECK_HEADERS(... net/foo.h ...)
AC_CHECK_HEADERS([net/if.h],,,
[#if HAVE_NET_FOO_H
# include <net/foo.h>
# endif
])

 More than one additional header may be required, but these cases should
 be rare, methinks.