Add missing FluidSynth checks, consistency tweak (#2109)

* Add missing FluidSynth check

* Fix check inconsistency

* Add more missing checks

Author: MrAlaux

src/i_oalmusic.c

@@ -439,7 +439,11 @@ static boolean I_OAL_InitMusic(int device)
     return false;
 }
 
-static int fl_gain, opl_gain;
+#if defined(HAVE_FLUIDSYNTH)
+static int fl_gain;
+#endif
+
+static int opl_gain;
 
 static void I_OAL_SetMusicVolume(int volume)
 {
@@ -609,7 +613,7 @@ static const char **I_OAL_DeviceList(void)
 
 static midiplayertype_t I_OAL_MidiPlayerType(void)
 {
-#ifdef HAVE_FLUIDSYNTH
+#if defined (HAVE_FLUIDSYNTH)
     if (active_module == &stream_fl_module)
     {
         return midiplayer_fluidsynth;

src/mn_setup.c

@@ -2492,13 +2492,15 @@ static void SetMidiPlayerOpl(void)
     }
 }
 
+#if defined(HAVE_FLUIDSYNTH)
 static void SetMidiPlayerFluidSynth(void)
 {
     if (I_MidiPlayerType() == midiplayer_fluidsynth)
     {
         SetMidiPlayer();
     }
 }
+#endif
 
 static void RestartMusic(void)
 {
@@ -2653,7 +2655,10 @@ static setup_menu_t music_settings1[] = {
 
 static void UpdateGainItems(void)
 {
+#if defined (HAVE_FLUIDSYNTH)
     DisableItem(auto_gain, music_settings1, "fl_gain");
+#endif
+
     DisableItem(auto_gain, music_settings1, "opl_gain");
 }