[PATCH 4 of 4 STABLE] chg: reset errno prior to calling strtol()

[Yuya Nishihara]

# HG changeset patch
# User Yuya Nishihara <yuya at tcha.org>
# Date 1604370261 -32400
#      Tue Nov 03 11:24:21 2020 +0900
# Branch stable
# Node ID 81da6feb5000140adb8972607415855953415233
# Parent  9534de20358f656be05e0633a3a2ba59932326f3
chg: reset errno prior to calling strtol()

Otherwise we can't figure out if the last strtol() invocation failed or
not.

diff --git a/contrib/chg/chg.c b/contrib/chg/chg.c
--- a/contrib/chg/chg.c
+++ b/contrib/chg/chg.c
@@ -276,6 +276,7 @@ static void execcmdserver(const struct c
 		debugmsg("closing files based on /proc contents");
 		struct dirent *de;
 		while ((de = readdir(dp))) {
+			errno = 0;
 			char *end;
 			long fd_value = strtol(de->d_name, &end, 10);
 			if (end == de->d_name) {