build: Use LIBASSUAN_CONFIG_LIBS (instead of LIB).
* configure.ac (LIBASSUAN_CONFIG_LIBS): Rename from *_LIB. (LIBASSUAN_CONFIG_EXTRA_LIBS): Remove. * src/libassuan-config.in: Follow the change. * src/libassuan.pc.in: Likewise.
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>