gmp:
 * do not test for C++ features at all if no C++ support is requested. Partial testing causes incorrect values to be cached in config.cache which in turn breaks compilation of some other packages.

p.s. I hate config.cache


git-svn-id: file:///var/svn/freetz/trunk@10101 149334a1-2f27-0410-a3b9-fc62619ac1e6