pgsql: Partial fixes for contrib build on AIX: include -lm where needed.

Log Message:
-----------
Partial fixes for contrib build on AIX: include -lm where needed.
Per Rocco Altier.

Modified Files:
--------------
    pgsql/contrib/cube:
        Makefile (r1.12 -> r1.13)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/cube/Makefile.diff?r1=1.12&r2=1.13)
    pgsql/contrib/earthdistance:
        Makefile (r1.14 -> r1.15)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/earthdistance/Makefile.diff?r1=1.14&r2=1.15)
    pgsql/contrib/tablefunc:
        Makefile (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tablefunc/Makefile.diff?r1=1.3&r2=1.4)
    pgsql/contrib/tsearch2:
        Makefile (r1.8 -> r1.9)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/Makefile.diff?r1=1.8&r2=1.9)
    pgsql/src/makefiles:
        Makefile.aix (r1.21 -> r1.22)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/makefiles/Makefile.aix.diff?r1=1.21&r2=1.22)