*: add "noexcept" to many, many function prototypes

This eliminates some overhead, because the compiler doesn't need to
consider these functions throwing.

src/player/Control.cxx

@@ -151,7 +151,7 @@ PlayerControl::LockSetBorderPause(bool _border_pause)
 }
 
 player_status
-PlayerControl::LockGetStatus()
+PlayerControl::LockGetStatus() noexcept
 {
 	player_status status;
 

src/player/Control.hxx

@@ -317,7 +317,7 @@ private:
 	 * To be called from the main thread.  Caller must lock the
 	 * object.
 	 */
-	void SynchronousCommand(PlayerCommand cmd) {
+	void SynchronousCommand(PlayerCommand cmd) noexcept {
 		assert(command == PlayerCommand::NONE);
 
 		command = cmd;
@@ -332,7 +332,7 @@ private:
 	 * To be called from the main thread.  This method locks the
 	 * object.
 	 */
-	void LockSynchronousCommand(PlayerCommand cmd) {
+	void LockSynchronousCommand(PlayerCommand cmd) noexcept {
 		const std::lock_guard<Mutex> protect(mutex);
 		SynchronousCommand(cmd);
 	}
@@ -383,7 +383,7 @@ public:
 	void Kill();
 
 	gcc_pure
-	player_status LockGetStatus();
+	player_status LockGetStatus() noexcept;
 
 	PlayerState GetState() const {
 		return state;

src/player/CrossFade.cxx

@@ -32,7 +32,7 @@ static constexpr Domain cross_fade_domain("cross_fade");
 
 gcc_pure
 static float
-mixramp_interpolate(const char *ramp_list, float required_db)
+mixramp_interpolate(const char *ramp_list, float required_db) noexcept
 {
 	float last_db = 0, last_secs = 0;
 	bool have_last = false;
@@ -91,7 +91,7 @@ CrossFadeSettings::Calculate(SignedSongTime total_time,
 			     const char *mixramp_start, const char *mixramp_prev_end,
 			     const AudioFormat af,
 			     const AudioFormat old_format,
-			     unsigned max_chunks) const
+			     unsigned max_chunks) const noexcept
 {
 	unsigned int chunks = 0;
 	float chunks_f;

src/player/CrossFade.hxx

@@ -66,7 +66,7 @@ struct CrossFadeSettings {
 			   const char *mixramp_start,
 			   const char *mixramp_prev_end,
 			   AudioFormat af, AudioFormat old_format,
-			   unsigned max_chunks) const;
+			   unsigned max_chunks) const noexcept;
 };
 
 #endif