pgsql: Provide a build-time option to store large relations as single

Log Message:
-----------
Provide a build-time option to store large relations as single files, rather
than dividing them into 1GB segments as has been our longtime practice. This
requires working support for large files in the operating system; at least for
the time being, it won't be the default.

Zdenek Kotala

Modified Files:
--------------
pgsql:
configure (r1.585 -> r1.586)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/configure?r1=1.585&r2=1.586)
configure.in (r1.552 -> r1.553)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/configure.in?r1=1.552&r2=1.553)
pgsql/doc/src/sgml:
installation.sgml (r1.303 -> r1.304)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/installation.sgml?r1=1.303&r2=1.304)
storage.sgml (r1.21 -> r1.22)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/storage.sgml?r1=1.21&r2=1.22)
pgsql/src/backend/storage/file:
buffile.c (r1.29 -> r1.30)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/file/buffile.c?r1=1.29&r2=1.30)
fd.c (r1.143 -> r1.144)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/file/fd.c?r1=1.143&r2=1.144)
pgsql/src/backend/storage/smgr:
md.c (r1.135 -> r1.136)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/smgr/md.c?r1=1.135&r2=1.136)
pgsql/src/backend/utils/sort:
tuplestore.c (r1.36 -> r1.37)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/sort/tuplestore.c?r1=1.36&r2=1.37)
pgsql/src/include:
pg_config.h.in (r1.128 -> r1.129)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/pg_config.h.in?r1=1.128&r2=1.129)
pg_config_manual.h (r1.28 -> r1.29)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/pg_config_manual.h?r1=1.28&r2=1.29)
pgsql/src/include/storage:
buffile.h (r1.23 -> r1.24)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/storage/buffile.h?r1=1.23&r2=1.24)
fd.h (r1.61 -> r1.62)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/storage/fd.h?r1=1.61&r2=1.62)