continue;
                }
 
-               if (skip_prefix(arg, "-S", &sign_commit))
+               if (!strcmp(arg, "--gpg-sign")) {
+                   sign_commit = "";
+                   continue;
+               }
+
+               if (skip_prefix(arg, "-S", &sign_commit) ||
+                       skip_prefix(arg, "--gpg-sign=", &sign_commit))
                        continue;
 
                if (!strcmp(arg, "--no-gpg-sign")) {