patch: fix configure warning

 
Hi,

The attached patch fixes the following warning thrown up by configure:

config.status: WARNING:  ../platforms/unix/config/make.cfg.in seems to ignore the --datarootdir setting

Built and tested on Linux (Ubuntu 8.04).

This patch was done against the 3.10-4 source tree, but it also applies
fine against today's SVN tree, when applied with "patch -p1 < ...".

Cheers,
Andrew Gaylard