commit dbd95cdaefdea95307d004f019a1c394cf9389f0
Author: fanquake <fanquake@gmail.com>
Date:   Mon Aug 17 20:15:17 2020 +0800

    Remove unused variable in Boost Process

    This causes issues with our linters / CI.

    Can be removed once depends Boost is 1.71.0 or later.

diff --git a/boost/process/detail/posix/wait_group.hpp b/boost/process/detail/posix/wait_group.hpp
index 9dc249803..2502d9772 100644
--- a/boost/process/detail/posix/wait_group.hpp
+++ b/boost/process/detail/posix/wait_group.hpp
@@ -137,7 +137,6 @@ inline bool wait_until(

     do
     {
-        int ret_sig = 0;
         int status;
         if ((::waitpid(timeout_pid, &status, WNOHANG) != 0)
             && (WIFEXITED(status) || WIFSIGNALED(status)))