pgsql: Improve some global variable declarations

Improve some global variable declarations

We have in launch_backend.c:

/*
* The following need to be available to the save/restore_backend_variables
* functions. They are marked NON_EXEC_STATIC in their home modules.
*/
extern slock_t *ShmemLock;
extern slock_t *ProcStructLock;
extern PGPROC *AuxiliaryProcs;
extern PMSignalData *PMSignalState;
extern pg_time_t first_syslogger_file_time;
extern struct bkend *ShmemBackendArray;
extern bool redirection_done;

That comment is not completely true: ShmemLock, ShmemBackendArray, and
redirection_done are not in fact NON_EXEC_STATIC. ShmemLock once was,
but was then needed elsewhere. ShmemBackendArray was static inside
postmaster.c before launch_backend.c was created. redirection_done
was never static.

This patch moves the declaration of ShmemLock and redirection_done to
a header file.

ShmemBackendArray gets a NON_EXEC_STATIC. This doesn't make a
difference, since it only exists if EXEC_BACKEND anyway, but it makes
it consistent.

After that, the comment is now correct.

Reviewed-by: Andres Freund <andres(at)anarazel(dot)de>
Discussion: https://www.postgresql.org/message-id/flat/e0a62134-83da-4ba4-8cdb-ceb0111c95ce(at)eisentraut(dot)org

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/8f8bcb88833eecfffbbb0d048ff0b6c33e64f7ce

Modified Files
--------------
src/backend/postmaster/launch_backend.c | 2 --
src/backend/postmaster/postmaster.c | 2 +-
src/backend/postmaster/syslogger.c | 2 --
src/backend/storage/lmgr/lwlock.c | 4 +---
src/backend/utils/error/elog.c | 2 --
src/include/postmaster/postmaster.h | 1 +
src/include/storage/shmem.h | 2 ++
7 files changed, 5 insertions(+), 10 deletions(-)