pgsql: pg_ctl: Detect current standby state from pg_control

pg_ctl: Detect current standby state from pg_control

pg_ctl used to determine whether a server was in standby mode by looking
for a recovery.conf file. With this change, it instead looks into
pg_control, which is potentially more accurate. There are also
occasional discussions about removing recovery.conf, so this removes one
dependency.

Reviewed-by: Michael Paquier <michael(dot)paquier(at)gmail(dot)com>

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/c1dc51d4844e2a37412b034c07c1c5a439ba0b9d

Modified Files
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src/backend/utils/misc/pg_controldata.c | 12 +++++++++
src/bin/pg_controldata/pg_controldata.c | 4 +++
src/bin/pg_ctl/pg_ctl.c | 47 ++++++++++++++++++++++++++-------
src/common/controldata_utils.c | 15 +++++------
src/include/common/controldata_utils.h | 2 +-
5 files changed, 62 insertions(+), 18 deletions(-)