pgsql: Remove dllist.c from libpq.

Log Message:
-----------
Remove dllist.c from libpq. It's overkill for what libpq needs; we can
just stick a list-link into struct PGnotify instead. Result is a smaller
faster and more robust library (mainly because we reduce the number of
malloc's and free's involved in notify processing), plus less pollution
of application link-symbol namespace.

Modified Files:
--------------
pgsql/src/include:
Makefile (r1.14 -> r1.15)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/Makefile.diff?r1=1.14&r2=1.15)
pgsql/src/interfaces/libpq:
Makefile (r1.119 -> r1.120)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/Makefile.diff?r1=1.119&r2=1.120)
bcc32.mak (r1.9 -> r1.10)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/bcc32.mak.diff?r1=1.9&r2=1.10)
fe-connect.c (r1.284 -> r1.285)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-connect.c.diff?r1=1.284&r2=1.285)
fe-exec.c (r1.162 -> r1.163)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-exec.c.diff?r1=1.162&r2=1.163)
fe-protocol2.c (r1.14 -> r1.15)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-protocol2.c.diff?r1=1.14&r2=1.15)
fe-protocol3.c (r1.17 -> r1.18)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-protocol3.c.diff?r1=1.17&r2=1.18)
libpq-fe.h (r1.110 -> r1.111)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/libpq-fe.h.diff?r1=1.110&r2=1.111)
libpq-int.h (r1.93 -> r1.94)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/libpq-int.h.diff?r1=1.93&r2=1.94)
win32.mak (r1.26 -> r1.27)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/win32.mak.diff?r1=1.26&r2=1.27)