Makefile.am: Link tests with required libraries, too.

Makefile.am: Link tests with required libraries, too.

"make check" fails on Solaris because libraries are missing:

      CCLD     test_common
    Undefined			first referenced
     symbol  			in file
    kc                          ./.libs/libcommon.a(common.o)
    kstat_data_lookup           ./.libs/libcommon.a(common.o)
    kstat_lookup                ./.libs/libcommon.a(common.o)
    kstat_read                  ./.libs/libcommon.a(common.o)
    getaddrinfo                 ./.libs/libcommon.a(common.o)
    freeaddrinfo                ./.libs/libcommon.a(common.o)
    gai_strerror                ./.libs/libcommon.a(common.o)
    ld: fatal: symbol referencing errors. No output written to test_common
    collect2: error: ld returned 1 exit status