cmake: make sure SDLMIXER_MIDI in SDL3_mixerConfig.cmake is valid

Author: madebr

CMakeLists.txt

@@ -883,6 +883,10 @@ if(SDLMIXER_MIDI_TIMIDITY)
     )
 endif()
 
+if(SDLMIXER_MIDI_FLUIDSYNTH_ENABLED OR SDLMIXER_MIDI_TIMIDITY_ENABLED)
+  set(SDLMIXER_MIDI_ENABLED TRUE)
+endif()
+
 list(APPEND SDLMIXER_BACKENDS WAVE)
 set(SDLMIXER_WAVE_ENABLED FALSE)
 if(SDLMIXER_WAVE)

cmake/SDL3_mixerConfig.cmake.in

@@ -8,7 +8,7 @@ set_package_properties(SDL3_mixer PROPERTIES
     DESCRIPTION "SDL_mixer is a sample multi-channel audio mixer library"
 )
 
-set(SDL3_mixer_FOUND                ON)
+set(SDL3_mixer_FOUND               ON)
 
 set(SDLMIXER_VENDORED              @SDLMIXER_VENDORED@)
 
@@ -28,7 +28,6 @@ set(SDLMIXER_MP3_MPG123            @SDLMIXER_MP3_MPG123_ENABLED@)
 
 set(SDLMIXER_MIDI                  @SDLMIXER_MIDI_ENABLED@)
 set(SDLMIXER_MIDI_FLUIDSYNTH       @SDLMIXER_MIDI_FLUIDSYNTH_ENABLED@)
-set(SDLMIXER_MIDI_NATIVE           @SDLMIXER_MIDI_NATIVE_ENABLED@)
 set(SDLMIXER_MIDI_TIMIDITY         @SDLMIXER_MIDI_TIMIDITY_ENABLED@)
 
 set(SDLMIXER_OPUS                  @SDLMIXER_OPUS_ENABLED@)