SDL_image: cmake: adjust dll name for os/2.

SDL Commits
1 
From 36675a366fb7b3fe1cd74c2e1b2f87734cf1ec3a Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Thu, 12 May 2022 14:00:10 +0300
Subject: [PATCH] cmake: adjust dll name for os/2.

---
 CMakeLists.txt | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 25031e4..225526e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -674,10 +674,16 @@ if (UNIX AND NOT APPLE AND NOT ANDROID)
         )
 endif()
 if (BUILD_SHARED_LIBS)
-    if (WIN32)
+    if (WIN32 OR OS2)
         set_target_properties(SDL2_image PROPERTIES
             PREFIX ""
             )
+    endif()
+    if (OS2)
+        # OS/2 doesn't support a DLL name longer than 8 characters.
+        set_target_properties(SDL2_image PROPERTIES
+            OUTPUT_NAME "SDL2img"
+            )
     elseif (UNIX AND NOT APPLE AND NOT ANDROID)
         set_target_properties(SDL2_image PROPERTIES
             OUTPUT_NAME "SDL2_image-${LT_RELEASE}"