pgbouncer - pgbouncer: use gcc attributes to uncover few correctness

Log Message:
-----------
use gcc attributes to uncover few correctness bugs

Modified Files:
--------------
pgbouncer/include:
admin.h (r1.1 -> r1.2)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/admin.h.diff?r1=1.1&r2=1.2)
bouncer.h (r1.5 -> r1.6)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/bouncer.h.diff?r1=1.5&r2=1.6)
client.h (r1.1 -> r1.2)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/client.h.diff?r1=1.1&r2=1.2)
janitor.h (r1.1 -> r1.2)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/janitor.h.diff?r1=1.1&r2=1.2)
loader.h (r1.1 -> r1.2)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/loader.h.diff?r1=1.1&r2=1.2)
objects.h (r1.2 -> r1.3)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/objects.h.diff?r1=1.2&r2=1.3)
pktbuf.h (r1.3 -> r1.4)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/pktbuf.h.diff?r1=1.3&r2=1.4)
pooler.h (r1.1 -> r1.2)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/pooler.h.diff?r1=1.1&r2=1.2)
proto.h (r1.1 -> r1.2)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/proto.h.diff?r1=1.1&r2=1.2)
sbuf.h (r1.3 -> r1.4)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/sbuf.h.diff?r1=1.3&r2=1.4)
server.h (r1.1 -> r1.2)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/server.h.diff?r1=1.1&r2=1.2)
slab.h (r1.1 -> r1.2)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/slab.h.diff?r1=1.1&r2=1.2)
stats.h (r1.1 -> r1.2)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/stats.h.diff?r1=1.1&r2=1.2)
system.h (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/system.h.diff?r1=1.4&r2=1.5)
takeover.h (r1.1 -> r1.2)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/takeover.h.diff?r1=1.1&r2=1.2)
util.h (r1.2 -> r1.3)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/util.h.diff?r1=1.2&r2=1.3)
varcache.h (r1.1 -> r1.2)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/varcache.h.diff?r1=1.1&r2=1.2)
pgbouncer/src:
admin.c (r1.23 -> r1.24)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/admin.c.diff?r1=1.23&r2=1.24)
main.c (r1.23 -> r1.24)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/main.c.diff?r1=1.23&r2=1.24)
objects.c (r1.32 -> r1.33)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/objects.c.diff?r1=1.32&r2=1.33)
pktbuf.c (r1.3 -> r1.4)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/pktbuf.c.diff?r1=1.3&r2=1.4)
pooler.c (r1.5 -> r1.6)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/pooler.c.diff?r1=1.5&r2=1.6)
server.c (r1.20 -> r1.21)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/server.c.diff?r1=1.20&r2=1.21)
takeover.c (r1.7 -> r1.8)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/takeover.c.diff?r1=1.7&r2=1.8)
util.c (r1.20 -> r1.21)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/util.c.diff?r1=1.20&r2=1.21)