This adds the log_temp_files GUC. All the other changes in this batch
we had backported already.

Conflicts:
	contrib/adminpack/adminpack.c
	contrib/pgbench/pgbench.c
	doc/README.mb.big5
	doc/TODO
	doc/src/FAQ/TODO.html
	doc/src/sgml/Makefile
	doc/src/sgml/charset.sgml
	doc/src/sgml/config.sgml
	doc/src/sgml/docguide.sgml
	src/backend/access/common/heaptuple.c
	src/backend/access/heap/heapam.c
	src/backend/storage/file/fd.c
	src/backend/utils/misc/postgresql.conf.sample
	src/include/access/heapam.h
	src/include/access/htup.h
	src/include/utils/guc.h
	src/tools/copyright
	src/tools/msvc/build.bat
	src/tools/msvc/gendef.pl