[pgpool-committers: 2457] pgpool: Fix to set SIGCHLD to SIG_DFL instead of SIG_IGN in watchdog pr

[Yugo Nagata]

Fix to set SIGCHLD to SIG_DFL instead of SIG_IGN in watchdog processes

When using waitpid, it isn't necessary to set SIGCHLD SIG_IGN. Rather,
waitpid returns ECHLD and WIFEXITED could be zero even when the child
process exit successfully. Due to this, it was recognized that ping
exited abnormally in error.

In addition, signal functions are replaced to pool_singal.

Branch
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V3_4_STABLE

Details
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http://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=ace897e6ec249dc608ebd76bfe82e3f16a7a6f02

Modified Files
--------------
src/watchdog/watchdog.c     |   13 ++++++-------
src/watchdog/wd_child.c     |   19 +++++++++----------
src/watchdog/wd_heartbeat.c |   37 ++++++++++++++++++-------------------
src/watchdog/wd_if.c        |    8 +-------
src/watchdog/wd_lifecheck.c |    1 -
src/watchdog/wd_ping.c      |    2 +-
6 files changed, 35 insertions(+), 45 deletions(-)