1 files changed, 1 insertions, 1 deletions

diff --git a/src/callproc.c b/src/callproc.c
index 07297820cac..7008b916dad 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -1094,7 +1094,7 @@ add_env (char **env, char **new_env, char *string)
       char *p = *ep, *q = string;
       while (ok)
         {
-          if (*q != *p)
+          if (*p && *q != *p)
             break;
           if (*q == 0)
             /* The string is a lone variable name; keep it for now, we