Implement MAKO::get_mark() for FM sound

It still does not work for MIDI.

src/android/mako.cpp

@@ -146,8 +146,14 @@ bool MAKO::check_music()
 
 void MAKO::get_mark(int* mark, int* loop)
 {
-	WARNING("not implemented");
-	*mark = *loop = 0;
+	SDL_LockMutex(fm_mutex);
+	if (fm) {
+		fm->get_mark(mark, loop);
+	} else {
+		*mark = 0;
+		*loop = 0;
+	}
+	SDL_UnlockMutex(fm_mutex);
 }
 
 void MAKO::play_pcm(int page, bool loop)

src/emscripten/mako.cpp

@@ -75,8 +75,12 @@ bool MAKO::check_music()
 
 void MAKO::get_mark(int* mark, int* loop)
 {
-	WARNING("not implemented");
-	*mark = *loop = 0;
+	if (fm) {
+		fm->get_mark(mark, loop);
+	} else {
+		*mark = 0;
+		*loop = 0;
+	}
 }
 
 void MAKO::play_pcm(int page, bool loop)

src/fm/mako_fmgen.cpp

@@ -60,3 +60,8 @@ void MakoFMgen::Mix(int samples) {
 	out_samples -= samples;
 	output += samples * 2;
 }
+
+void MakoFMgen::get_mark(int* mark, int* loop) {
+	*mark = GetMark();
+	*loop = Looped() ? 1 : 0;
+}

src/fm/mako_fmgen.h

@@ -8,6 +8,7 @@ class MakoFMgen : private MakoFM {
 public:
 	MakoFMgen(int rate, const uint8_t* data, bool free_data);
 	void Process(int16* stream, int len);
+	void get_mark(int* mark, int* loop);
 
 private:
 	void SetReg(RegType type, uint8_t addr, uint8_t val) override;

src/fm/makofm.h

@@ -18,6 +18,7 @@ public:
 
 	double GetTime() const { return time_ms; }
 	bool Looped() const { return part_looped == (1 << MAKO_MAXCH) - 1; }
+	uint8_t GetMark() const { return current_mark; }
 
 protected:
 	enum RegType {

src/linux/mako.cpp

@@ -158,9 +158,14 @@ bool MAKO::check_music()
 
 void MAKO::get_mark(int* mark, int* loop)
 {
-	// TODO: fix
-	*mark = 0;
-	*loop = 0;
+	SDL_LockMutex(fm_mutex);
+	if (fm) {
+		fm->get_mark(mark, loop);
+	} else {
+		*mark = 0;
+		*loop = 0;
+	}
+	SDL_UnlockMutex(fm_mutex);
 }
 
 void MAKO::play_pcm(int page, bool loop)

src/win/mako.cpp

@@ -418,9 +418,14 @@ void MAKO::select_sound(BGMDevice dev)
 
 void MAKO::get_mark(int* mark, int* loop)
 {
-	// TODO: fix
-	*mark = 0;
-	*loop = 0;
+	SDL_LockMutex(fm_mutex);
+	if (fm) {
+		fm->get_mark(mark, loop);
+	} else {
+		*mark = 0;
+		*loop = 0;
+	}
+	SDL_UnlockMutex(fm_mutex);
 }
 
 void MAKO::play_pcm(int page, bool loop)