--- misc-utils/cal.c
+++ misc-utils/cal.c
@@ -702,18 +702,16 @@
 }
 
 void
-trim_trailing_spaces(s)
-	char *s;
+trim_trailing_spaces(char *s)
 {
 	char *p;
 
 	for (p = s; *p; ++p)
 		continue;
-	while (p > s && isspace(*--p))
-		continue;
-	if (p > s)
-		++p;
-	*p = '\0';
+
+	p--;
+	if (isspace(*p))
+		*p = '\0';
 }
 
 /*