gconfig: fix build failure on fedora 13

Making gconfig fails on fedora 13 as the linker cannot resolve dlsym.

Adding libdl to the link command fixes this.

make shows this error :-
    /usr/bin/ld: scripts/kconfig/kconfig_load.o: undefined reference to symbol 'dlsym@@GLIBC_2.2.5'
    /usr/bin/ld: note: 'dlsym@@GLIBC_2.2.5' is defined in DSO /lib64/libdl.so.2 so try adding it to the linker command line
    /lib64/libdl.so.2: could not read symbols: Invalid operation

tested on x86_64 fedora 13.

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>