[SV 63981] Don't warn on explicit -j1

If -j1 is given explicitly on the command line don't warn about it.

* src/main.c (main): Skip the warning if -j1.
* tests/scripts/features/jobserver: Add a test for this behavior.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/main.c b/src/main.c
index 5d6b9e76..8587de61 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1830,7 +1830,7 @@ main (int argc, char **argv, char **envp)
 
       /* The user provided a -j setting on the command line so use it: we're
          the master make of a new jobserver group.  */
-      else if (!restarts)
+      else if (!restarts && argv_slots != 1)
         ON (error, NILF,
             _("warning: -j%d forced in submake: resetting jobserver mode"),
             argv_slots);