jobs: Fix waitcmd busy loop

We need to clear gotsigchld in waitproc because it is used as
a loop conditional for the waitcmd case.  Without it waitcmd
may busy loop after a SIGCHLD.

This patch also changes gotsigchld into a volatile sig_atomic_t
to prevent compilers from optimising its accesses away.

Fixes: 6c691b3e5099 ("jobs: Only clear gotsigchld when waiting...")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
3 files changed