Remove unused SDL dependency

CMake/DefineOptions.cmake

@@ -63,8 +63,6 @@ option(WITH_SYSTEM_JPEG "Build with system jpeglib" OFF)
 option(WITH_SYSTEM_PCRE "Build with system PCRE" OFF)
 option(WITH_SYSTEM_ZLIB "Build against system zlib" OFF)
 
-option(WITH_SDL "Build with SDL" OFF)
-
 if(NOT MSVC)
   # Turn this option off to disable using FFMEPG.
   option(WITH_FFMPEG "Build with FFMPEG." ON)

StepmaniaCore.cmake

@@ -256,11 +256,6 @@ if(WITH_OGG)
   endif()
 endif()
 
-if(WITH_SDL)
-  find_package(SDL2 REQUIRED)
-  set(HAS_SDL TRUE)
-endif()
-
 find_package(nasm)
 find_package(yasm)
 

src/CMakeLists.txt

@@ -623,11 +623,6 @@ else() # Unix / Linux TODO: Remember to find and locate the zip archive files.
     list(APPEND SMDATA_LINK_LIB ${X11_LIBRARIES})
   endif()
 
-  if(SDL2_FOUND)
-    list(APPEND SMDATA_LINK_LIB ${SDL2_LIBRARY})
-    target_compile_definitions("${SM_EXE_NAME}" PRIVATE HAVE_SDL)
-  endif()
-
   if(PCRE_FOUND)
     list(APPEND SMDATA_LINK_LIB ${PCRE_LIBRARY})
   endif()