SDL: cmake: install LICENSE.txt

SDL Commits
1 
From fb7c03ebb5ac903d081efdc667564fe80a043e50 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <[EMAIL REDACTED]>
Date: Wed, 15 Jun 2022 03:04:10 +0200
Subject: [PATCH] cmake: install LICENSE.txt

---
 CMakeLists.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 524481d6719..9a6a49b6284 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3169,6 +3169,7 @@ if(NOT SDL2_DISABLE_INSTALL)
     install(PROGRAMS ${SDL2_BINARY_DIR}/sdl2-config DESTINATION "${CMAKE_INSTALL_BINDIR}")
     # TODO: what about the .spec file? Is it only needed for RPM creation?
     install(FILES "${SDL2_SOURCE_DIR}/sdl2.m4" DESTINATION "${CMAKE_INSTALL_DATAROOTDIR}/aclocal")
+    install(FILES "LICENSE.txt" DESTINATION "${CMAKE_INSTALL_DATAROOTDIR}/licenses/${PROJECT_NAME}")
   endif()
 endif()