pgsql: Use sys_siglist[] to print out signal names for signal exits,

Log Message:
-----------
Use sys_siglist[] to print out signal names for signal exits, rather
than just numbers.

Modified Files:
--------------
    pgsql:
        configure (r1.530 -> r1.531)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/configure.diff?r1=1.530&r2=1.531)
        configure.in (r1.497 -> r1.498)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/configure.in.diff?r1=1.497&r2=1.498)
    pgsql/src/backend/postmaster:
        postmaster.c (r1.512 -> r1.513)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/postmaster/postmaster.c.diff?r1=1.512&r2=1.513)
    pgsql/src/include:
        pg_config.h.in (r1.108 -> r1.109)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/pg_config.h.in.diff?r1=1.108&r2=1.109)
    pgsql/src/port:
        exec.c (r1.48 -> r1.49)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/port/exec.c.diff?r1=1.48&r2=1.49)