commit 727b2a5236346e75ec6455179d5073e348d165be (HEAD -> refs/heads/master, refs/remotes/origin/master, refs/remotes/origin/HEAD)
Author: Érico Rolim <erico.erc@gmail.com>
Date:   Wed Aug 26 21:00:34 2020 -0300

    chpst: fix undefined operation on sequence point.
    
    Based on patch from
    
    https://salsa.debian.org/debian/runit/-/blob/77a49befd7c1a08bfe0613454e540562529811fa/debian/patches/0016-fix-warning-for-undefined-operation-on-sequence-poin.patch

diff --git a/src/chpst.c b/src/chpst.c
index f279d44..1cca5f4 100644
--- a/runit-2.1.2/src/chpst.c
+++ b/runit-2.1.2/src/chpst.c
@@ -308,7 +308,8 @@ int main(int argc, const char **argv) {
     case 'n':
       switch (*optarg) {
         case '-':
-          if (optarg[scan_ulong(++optarg, &ul)]) usage(); nicelvl =ul;
+          ++optarg;
+          if (optarg[scan_ulong(optarg, &ul)]) usage(); nicelvl =ul;
           nicelvl *=-1;
           break;
         case '+': ++optarg;