SDL_image: Make sure to pick up libjxl's third party dependencies

From 2a00234b5c95fa12dfe054dc2bbbc3e9a0129232 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Tue, 10 May 2022 11:34:48 -0700
Subject: [PATCH] Make sure to pick up libjxl's third party dependencies

---
 external/download.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/external/download.sh b/external/download.sh
index 2ab7cbb..5cd14a4 100755
--- a/external/download.sh
+++ b/external/download.sh
@@ -12,5 +12,5 @@ while true; do
     url=$3
     read line; set -- $line
     branch=$3
-    git clone $url $path -b $branch
+    git clone $url $path -b $branch --recursive
 done