compiler fixes

* DStarRepeater/DStarRepeaterApp.cpp

    suggest explicit braces to avoid ambiguous ‘else’

 * Common/AudioCallback.h
 * Common/SoundCardController.cpp
 * Common/SoundCardController.h
 * Common/SoundCardReaderWriter.cpp

    comparison between signed and unsigned integer expressions

    backport from MMDVM-UDRC "Fix signed integer issues with compiler"
    by mcdermj

    fix issue #4

Common/AudioCallback.h

@@ -19,7 +19,7 @@
 class IAudioCallback {
 public:
 	virtual void readCallback(const wxFloat32* input, unsigned int nSamples, int id) = 0;
-	virtual void writeCallback(wxFloat32* output, unsigned int& nSamples, int id) = 0;
+	virtual void writeCallback(wxFloat32* output, int& nSamples, int id) = 0;
 
 private:
 };

Common/SoundCardController.cpp

@@ -591,7 +591,7 @@ void CSoundCardController::readCallback(const wxFloat32* input, unsigned int n,
 #endif
 }
 
-void CSoundCardController::writeCallback(wxFloat32* output, unsigned int& n, int id)
+void CSoundCardController::writeCallback(wxFloat32* output, int& n, int id)
 {
         if (n == 0U)
                 return;

Common/SoundCardController.h

@@ -52,7 +52,7 @@ public:
 	virtual bool writeData(const unsigned char* data, unsigned int length, bool end);
 
 	virtual void readCallback(const wxFloat32* input, unsigned int n, int id);
-	virtual void writeCallback(wxFloat32* output, unsigned int& n, int id);
+	virtual void writeCallback(wxFloat32* output, int& n, int id);
 
 private:
 	CSoundCardReaderWriter     m_sound;

Common/SoundCardReaderWriter.cpp

@@ -730,25 +730,25 @@ void* CSoundCardWriter::Entry()
 	wxLogMessage(wxT("Starting ALSA writer thread"));
 
 	while (!m_killed) {
-		unsigned int nSamples = 2U * m_blockSize;
+		int nSamples = 2U * m_blockSize;
 		m_callback->writeCallback(m_buffer, nSamples, m_id);
 
 		if (nSamples == 0U) {
 			Sleep(5UL);
 		} else {
 			if (m_channels == 1U) {
-				for (unsigned int n = 0U; n < nSamples; n++)
+				for (int n = 0U; n < nSamples; n++)
 					m_samples[n] = short(m_buffer[n] * 32767.0F);
 			} else {
-				unsigned int i = 0U;
+				int i = 0U;
-				for (unsigned int n = 0U; n < nSamples; n++) {
+				for (int n = 0U; n < nSamples; n++) {
 					short sample = short(m_buffer[n] * 32767.0F);
 					m_samples[i++] = sample;
 					m_samples[i++] = sample;			// Same value to both channels
 				}
 			}
         
-			unsigned int offset = 0U;
+			int offset = 0U;
 			snd_pcm_sframes_t ret;
 			while ((ret = ::snd_pcm_writei(m_handle, m_samples + offset, nSamples - offset)) != (nSamples - offset)) {
 				if (ret < 0) {
@@ -759,7 +759,7 @@ void* CSoundCardWriter::Entry()
 
 					::snd_pcm_recover(m_handle, ret, 1);
 				} else {
-					offset += (unsigned int)ret;
+					offset += ret;
 				}
 			}
 		}

DStarRepeater/DStarRepeaterApp.cpp

@@ -503,14 +503,16 @@ void CDStarRepeaterApp::createThread()
 		wxLogInfo("Split, local: %s:%u, timeout: %u ms", localAddress.c_str(), localPort, timeout);
 		for (unsigned int i = 0U; i < transmitterNames.GetCount(); i++) {
 			wxString name = transmitterNames.Item(i);
-			if (!name.IsEmpty())
+			if (!name.IsEmpty()) {
 				wxLogInfo("\tTX %u name: %s", i + 1U, name.c_str());
 			}
+		}
 		for (unsigned int i = 0U; i < receiverNames.GetCount(); i++) {
 			wxString name = receiverNames.Item(i);
-			if (!name.IsEmpty())
+			if (!name.IsEmpty()) {
 				wxLogInfo("\tRX %u name: %s", i + 1U, name.c_str());
 			}
+		}
 		modem = new CSplitController(localAddress, localPort, transmitterNames, receiverNames, timeout);
 	} else if (modemType.IsSameAs("Icom Access Point/Terminal Mode")) {
 		wxString port;