patch 8.2.0035: saving and restoring called_emsg is clumsy

Problem:    Saving and restoring called_emsg is clumsy.
Solution:   Count the number of error messages.
diff --git a/src/main.c b/src/main.c
index 72e51a3..eec02ea 100644
--- a/src/main.c
+++ b/src/main.c
@@ -4140,7 +4140,7 @@
 	    if (xterm_dpy != NULL)
 		res = serverGetVimNames(xterm_dpy);
 # endif
-	    if (called_emsg)
+	    if (did_emsg)
 		mch_errmsg("\n");
 	}
 	else if (STRICMP(argv[i], "--servername") == 0)