BACKENDS: Implement logging API proposed by Max on -devel.

This commits a slightly modified patch from my patch tracker item #3104630
"OSYSTEM: Add logging API as proposed by Max on -devel".

I was not able to test compilation on Android and SamsungTV, since there is no
toolchain for those on buildbot (or I was too blind to find them).

svn-id: r54339

backends/platform/psp/osys_psp.cpp

@@ -408,6 +408,13 @@ void OSystem_PSP::quit() {
 	sceKernelExitGame();
 }
 
+void OSystem_PSP::logMessage(LogMessageType::Type type, const char *message) {
+	BaseBackend::logMessage(type, message);
+
+	if (type == LogMessageType::kError)
+		PspDebugTrace(false, "%s", message);	// write to file
+}
+
 void OSystem_PSP::getTimeAndDate(TimeDate &td) const {
 	time_t curTime = time(0);
 	struct tm t = *localtime(&curTime);

backends/platform/psp/osys_psp.h

@@ -153,6 +153,8 @@ public:
 
 	void quit();
 
+	void logMessage(LogMessageType::Type type, const char *message);
+
 	Common::SeekableReadStream *createConfigReadStream();
 	Common::WriteStream *createConfigWriteStream();