pgsql: Add 'output file' option for pg_dumpall, especially useful for

Log Message:
-----------
Add 'output file' option for pg_dumpall, especially useful for Win32,
where output redirection of child processes (pg_dump) doesn't work.

Dave Page

Modified Files:
--------------
    pgsql/doc/src/sgml/ref:
        pg_dumpall.sgml (r1.61 -> r1.62)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/pg_dumpall.sgml.diff?r1=1.61&r2=1.62)
    pgsql/src/bin/pg_dump:
        pg_backup.h (r1.44 -> r1.45)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_backup.h.diff?r1=1.44&r2=1.45)
        pg_backup_archiver.c (r1.139 -> r1.140)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_backup_archiver.c.diff?r1=1.139&r2=1.140)
        pg_backup_archiver.h (r1.73 -> r1.74)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_backup_archiver.h.diff?r1=1.73&r2=1.74)
        pg_dump.c (r1.458 -> r1.459)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_dump.c.diff?r1=1.458&r2=1.459)
        pg_dumpall.c (r1.88 -> r1.89)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_dumpall.c.diff?r1=1.88&r2=1.89)
    pgsql/src/include:
        c.h (r1.216 -> r1.217)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/c.h.diff?r1=1.216&r2=1.217)