headers "present but cannot be compiled" for autoconf 2.53

[Tim Potter]

Is anyone else annoyed by these guys?

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 bug-autoconf at gnu.org. ##
configure: WARNING:     ## ------------------------------------ ##

Apparently the semantics of AC_CHECK_HEADERS has changed between 2.13 and
2.53 so that header files have to actually compile instead of simply pass
through cpp.  I'm a bit reluctant to have to maintain header file
dependencies as the exact header files required are going to vary greatly
upon what is installed on the host machine.

My favourite idea at the moment is to replace AC_CHECK_HEADERS with a
macro that reinstates the old semantics.  

Any comments from anyone else?  It's also bugzilla bug 350.


Tim.