pgsql: Move PG_TEMP_FILE* macros to file_utils.h.

Move PG_TEMP_FILE* macros to file_utils.h.

Presently, frontend code that needs to use these macros must either
include storage/fd.h, which declares several frontend-unsafe
functions, or duplicate the macros. This commit moves these macros
to common/file_utils.h, which is safe for both frontend and backend
code. Consequently, we can also remove the duplicated macros in
pg_checksums and stop including storage/fd.h in pg_rewind.

Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/ZOP5qoUualu5xl2Z%40paquier.xyz

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/f39b265808bde307953dd4bd46dca1f58f0988e8

Modified Files
--------------
src/backend/backup/basebackup.c | 2 +-
src/backend/postmaster/postmaster.c | 1 +
src/backend/storage/file/fileset.c | 1 +
src/bin/pg_checksums/pg_checksums.c | 10 ----------
src/bin/pg_rewind/filemap.c | 2 +-
src/include/common/file_utils.h | 4 ++++
src/include/storage/fd.h | 4 ----
7 files changed, 8 insertions(+), 16 deletions(-)