sdl12-compat: fixed typo in a comment.

From 4c20f0214a5def81da99d29de5c544e03b0f66f5 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Sat, 27 Feb 2021 17:30:56 +0300
Subject: [PATCH] fixed typo in a comment.

---
 CMakeLists.txt | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3c2e04e..6399321 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 # NOTE:  If you installed SDL2 at an unusual place and FindSDL2 fails,
-#        you can define SDL2_INCLUDE_DIRS on the cmdline. For example:
-#        cmake -DSDL2_INCLUDE_DIRS=/opt/SDL2/include/SDL2 [other opts]
+#        you can define SDL2_INCLUDE_DIR on the cmdline.  For example:
+#        cmake -DSDL2_INCLUDE_DIR=/opt/SDL2/include/SDL2 [other stuff]
 
 cmake_minimum_required(VERSION 3.0.0)
 project(sdl12_compat)