Configure check for smbwrapper

[Andrew Tridgell]

> Hmm...  Can I just set _RLD_LIST as well as LD_PRELOAD in my test? 

I think it would be better to extract the code out of smbsh.c into a
function then call that function in the test.

> This assumes that running $CC $LDSHFLAGS $CFLAGS generates a 16 bit
> (?)  executable

16 bit? the old IRIX binary format isn't as good as their newer ones
but it certainly ins't 16 bit :)

> to use or do I have to built multiple versions of the shared
> libraries to test?

depends how strict you want to be with the test :)