Supressing output from AC_CHECK_DECL

[jcurlmail]

Hello,

I'm still trying to figure out how to get around preventing output during the 
./configure check and I'm still stuck. I can't seem to find anything relevant 
in the M4 manual, or the autoconf manual.

When I use AC_CHECK_DECL, how can I prevent it from outputting to the console 
for a specific message only? I don't want to supress all messages, only one 
specific message (and replace it with my own, more complex reusable macro).

I've looked at the sources and see it ultimately uses AC_MESSAGE_FD and this is 
fixed with a value of 6. There's no magic variables it uses to override this 
with /dev/null. I've seen I can override this macro with my own by just 
defining a macro of the same name, but I want to only temporarily override it. 

I see that m4_pushdef, m4_define, m4_defn, m4_popdef may all help, but being 
new to m4, I'm still trying to figure out what the m4 manuals mean. 
Alternatively, in 'acgeneral.m4' I see AC_DIVERT_PUSH and wondering if this is 
appropriate (I don't see any documentation for this in the autoconf manual).

In the end, I've done:
pushdef([AS_MESSAGE_FD], [/dev/null])
popdef([AS_MESSAGE_FD])

It appears to work. But again, I've not got much experience in this area - can 
I expect to see problems, or is there another way that is more portable,

Thanks for your patience,
Jason.