Fix new Clang compielr warnings

* returning bool from main
* set-but-unused variables
* mismatch of bitwise and logical 'or'

src/Instrumentation/HUD/HUD_runway.cxx

@@ -136,10 +136,10 @@ void HUD::Runway::draw()
     glEnable(GL_LINE_STIPPLE);
     glLineStipple(1, _stipple_out);
     anyLines =
-            drawLine(_points3d[0], _points3d[1], _points2d[0], _points2d[1]) | //draw top
-            drawLine(_points3d[2], _points3d[1], _points2d[2], _points2d[1]) | //draw right
-            drawLine(_points3d[2], _points3d[3], _points2d[2], _points2d[3]) | //draw bottom
-            drawLine(_points3d[3], _points3d[0], _points2d[3], _points2d[0]);  //draw left
+        drawLine(_points3d[0], _points3d[1], _points2d[0], _points2d[1]) || //draw top
+        drawLine(_points3d[2], _points3d[1], _points2d[2], _points2d[1]) || //draw right
+        drawLine(_points3d[2], _points3d[3], _points2d[2], _points2d[3]) || //draw bottom
+        drawLine(_points3d[3], _points3d[0], _points2d[3], _points2d[0]);   //draw left
 
     glLineStipple(1, _stipple_center);
     anyLines |= drawLine(_points3d[5], _points3d[4], _points2d[5], _points2d[4]); //draw center

src/Network/Swift/plugin.cpp

@@ -15,13 +15,6 @@
 #include <simgear/structure/commands.hxx>
 #include <thread>
 
-namespace {
-inline std::string fgswiftbusServiceName()
-{
-    return "org.swift-project.fgswiftbus";
-}
-} // namespace
-
 namespace FGSwiftBus {
 CPlugin::CPlugin()
 {

src/Network/Swift/plugin.h

@@ -50,7 +50,6 @@ private:
     std::unique_ptr<CTraffic> m_traffic;
 
     std::thread m_dbusThread;
-    bool m_isRunning = false;
     bool m_shouldStop = false;
 };
 } // namespace FGSwiftBus

src/Traffic/Schedule.cxx

@@ -583,16 +583,13 @@ FGScheduledFlight* FGAISchedule::findAvailableFlight(const string& currentDestin
     if (fltBegin == fltEnd) {
         SG_LOG(SG_AI, SG_BULK, "No Flights Scheduled for " << req);
     }
-    int counter = 0;
+
     for (FGScheduledFlightVecIterator i = fltBegin; i != fltEnd; ++i) {
         (*i)->adjustTime(now);
-        //sort(fltBegin, fltEnd, compareScheduledFlights);
-        //cerr << counter++ << endl;
     }
     std::sort(fltBegin, fltEnd, FGScheduledFlight::compareScheduledFlights);
     for (FGScheduledFlightVecIterator i = fltBegin; i != fltEnd; ++i) {
         //bool valid = true;
-        counter++;
         if (!(*i)->isAvailable()) {
             SG_LOG(SG_AI, SG_BULK, "" << (*i)->getCallSign() << "is no longer available");
 

utils/GPSsmooth/MIDG_main.cxx

@@ -8,6 +8,7 @@
 #  include <netinet/in.h>       // htonl() ntohl()
 #endif
 
+#include <cstdlib>
 #include <iostream>
 #include <string>
 
@@ -574,19 +575,19 @@ int main( int argc, char **argv ) {
         SGSerialPort input( serialdev, 115200 );
         if ( !input.is_enabled() ) {
             cout << "Cannot open: " << serialdev << endl;
-            return false;
+            return EXIT_FAILURE;
         }
 
         // open up the data log file if requested
         if ( !outfile.length() ) {
             cout << "no --outfile <name> specified, cannot capture data!"
                  << endl;
-            return false;
+            return EXIT_FAILURE;
         }
         SGFile output( outfile );
         if ( !output.open( SG_IO_OUT ) ) {
             cout << "Cannot open: " << outfile << endl;
-            return false;
+            return EXIT_FAILURE;
         }
 
         while ( input.is_enabled() ) {

utils/GPSsmooth/UGear_main.cxx

@@ -8,6 +8,7 @@
 #  include <netinet/in.h>       // htonl() ntohl()
 #endif
 
+#include <cstdlib>
 #include <iostream>
 #include <string>
 
@@ -990,7 +991,6 @@ int main( int argc, char **argv ) {
     } else if ( serialdev.length() ) {
         // process incoming data from the serial port
 
-        int count = 0;
         double current_time = 0.0;
         double last_time = 0.0;
 
@@ -1012,19 +1012,19 @@ int main( int argc, char **argv ) {
         SGSerialPort uavcom( serialdev, 115200 );
         if ( !uavcom.is_enabled() ) {
             cout << "Cannot open: " << serialdev << endl;
-            return false;
+            return EXIT_FAILURE;
         }
 
         // open up the data log file if requested
         if ( !outfile.length() ) {
             cout << "no --outfile <name> specified, cannot capture data!"
                  << endl;
-            return false;
+            return EXIT_FAILURE;
         }
         SGFile log( outfile );
         if ( !log.open( SG_IO_OUT ) ) {
             cout << "Cannot open: " << outfile << endl;
-            return false;
+            return EXIT_FAILURE;
         }
 
         // add some test commands
@@ -1039,7 +1039,6 @@ int main( int argc, char **argv ) {
 					 &imupacket, &navpacket, &servopacket,
 					 &healthpacket, ignore_checksum );
             // cout << "message id = " << id << endl;
-            count++;
 
             telnet.process();