static sdl2 compilation option for Unixes that are not Apple

CMakeLists.txt

@@ -31,6 +31,7 @@ configure_file ("${OpenMW_SOURCE_DIR}/Docs/mainpage.hpp.cmake" "${OpenMW_SOURCE_
 option(MYGUI_STATIC "Link static build of Mygui into the binaries" FALSE)
 option(OGRE_STATIC  "Link static build of Ogre and Ogre Plugins into the binaries" FALSE)
 option(BOOST_STATIC "Link static build of Boost into the binaries" FALSE)
+option(SDL2_STATIC "Link static build of SDL into the binaries" FALSE)
 
 # Apps and tools
 option(BUILD_BSATOOL "build BSA extractor" OFF)

cmake/FindSDL2.cmake

@@ -183,3 +183,11 @@ INCLUDE(FindPackageHandleStandardArgs)
 
 FIND_PACKAGE_HANDLE_STANDARD_ARGS(SDL2
                                   REQUIRED_VARS SDL2_LIBRARY SDL2_INCLUDE_DIR)
+
+IF(SDL2_STATIC)
+  if (UNIX AND NOT APPLE)
+    EXECUTE_PROCESS(COMMAND sdl2-config --static-libs OUTPUT_VARIABLE SDL2_LINK_FLAGS)
+    STRING(REGEX REPLACE "(\r?\n)+$" "" SDL2_LINK_FLAGS "${SDL2_LINK_FLAGS}")
+    SET(SDL2_LIBRARY ${SDL2_LINK_FLAGS})
+  ENDIF()
+ENDIF(SDL2_STATIC)