SDL: CMake: Fix SOVERSION/SONAME of non-release versions

SDL Commits
1 
From e2234ee97c929345b065fe355fe6c8d2a394f2af Mon Sep 17 00:00:00 2001
From: Daniel Gibson <[EMAIL REDACTED]>
Date: Sun, 16 May 2021 06:33:29 +0200
Subject: [PATCH] CMake: Fix SOVERSION/SONAME of non-release versions

When building SDL2 from git with CMake, you got libSDL2-2.0.so.1
instead of .0 (as it's the case when building with autotools).
This was caused by using LT_REVISION instead of LT_MAJOR for SOVERSION.

fixes #4310
---
 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 07da97ad6..690220714 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2530,7 +2530,7 @@ if(SDL_SHARED)
   elseif(UNIX AND NOT ANDROID)
     set_target_properties(SDL2 PROPERTIES
       VERSION ${LT_VERSION}
-      SOVERSION ${LT_REVISION}
+      SOVERSION ${LT_MAJOR}
       OUTPUT_NAME "SDL2-${LT_RELEASE}")
   else()
     if(WINDOWS OR CYGWIN)