configure option to disable tests

[Ciprian Dorin Craciun]

    Hello all!

    I'm writing this to make a small suggestion: it would be nice to
have an option to disable the tests when building and installing.

    I'm asking this because I want to install libgcrypt to a
non-standard location (ex. /packages/libgcrypt--1.4.1), and after
installing it I want to symlink all includes and libs into
/packages/.include /packages/.lib, but the tests fail by not finding
the includes and libs (as they haven't been symlink-ed yet).

    Thanks all,
    Ciprian Craciun.