Do not call ldconfig when building Debian package

Do not call ldconfig when building Debian package

Hi,

If I want to build Debian package, it fails with the following message:

    ldconfig: Can't create temporary cache file /etc/ld.so.cache~: Permission denied
    make[1]: *** [install-lib] Error 1

The reason is that I build the package as a non-root user and make
install invokes ldconfig unconditionally. The following patch contains a
workaround, but I think that a more correct solution would be to check
the condition LIBDIR_IN_LDCONFIG directly when make install is invoked
rather than in configure as it is done now.

Signed-off-by: Michal Sojka <sojkam1@fel.cvut.cz>