pgsql: Add fprintf() custom version to libpgport.

Log Message:
-----------
Add fprintf() custom version to libpgport.

Document use of macros for pg_printf functions.

Bump major versions of all interfaces to handle movement of get_progname
from libpq to libpgport in 8.0, and probably other libpgport changes in 8.1.

Modified Files:
--------------
pgsql/src/backend/bootstrap:
bootscanner.l (r1.38 -> r1.39)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/bootstrap/bootscanner.l.diff?r1=1.38&r2=1.39)
pgsql/src/backend/parser:
scan.l (r1.120 -> r1.121)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/scan.l.diff?r1=1.120&r2=1.121)
pgsql/src/backend/utils/misc:
guc-file.l (r1.29 -> r1.30)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/guc-file.l.diff?r1=1.29&r2=1.30)
pgsql/src/include:
port.h (r1.71 -> r1.72)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/port.h.diff?r1=1.71&r2=1.72)
pgsql/src/interfaces/ecpg/compatlib:
Makefile (r1.19 -> r1.20)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/compatlib/Makefile.diff?r1=1.19&r2=1.20)
pgsql/src/interfaces/ecpg/ecpglib:
Makefile (r1.31 -> r1.32)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/ecpglib/Makefile.diff?r1=1.31&r2=1.32)
pgsql/src/interfaces/ecpg/pgtypeslib:
Makefile (r1.24 -> r1.25)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/pgtypeslib/Makefile.diff?r1=1.24&r2=1.25)
pgsql/src/interfaces/ecpg/preproc:
Makefile (r1.112 -> r1.113)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/preproc/Makefile.diff?r1=1.112&r2=1.113)
pgsql/src/interfaces/libpq:
Makefile (r1.128 -> r1.129)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/Makefile.diff?r1=1.128&r2=1.129)
pgsql/src/pl/plpgsql/src:
scan.l (r1.39 -> r1.40)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/scan.l.diff?r1=1.39&r2=1.40)
pgsql/src/port:
snprintf.c (r1.17 -> r1.18)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/port/snprintf.c.diff?r1=1.17&r2=1.18)
pgsql/src/tools:
RELEASE_CHANGES (r1.56 -> r1.57)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/RELEASE_CHANGES.diff?r1=1.56&r2=1.57)