- give gpg-error-config libdir=@exec_prefix@/lib instead of @libdir@, so
        that it agrees on 32- and 64-bit arches (it suppresses the -L argument
        if @libdir@ is /usr/lib, so this should be cleaner than adding a
        non-standard .pc file which upstream developers might inadvertently
        think they can depend to be on every system which provides this
        library)