make gps optional. Portduino almost works in sim!

platformio.ini

@@ -251,6 +251,6 @@ lib_deps =
 [env:linux]
 platform = https://github.com/geeksville/platform-portduino.git
 src_filter = ${env.src_filter} -<esp32/> -<nimble/> -<nrf52/>
-build_flags = ${arduino_base.build_flags} 
+build_flags = ${arduino_base.build_flags} -O0
 framework = arduino
 board = linux_x86_64

src/main.cpp

@@ -268,7 +268,10 @@ void setup()
     gps = new NEMAGPS();
     gps->setup();
 #endif
-    gpsStatus->observe(&gps->newStatus);
+    if (gps)
+        gpsStatus->observe(&gps->newStatus);
+    else
+        DEBUG_MSG("Warning: No GPS found - running without GPS\n");
     nodeStatus->observe(&nodeDB.newStatus);
 
     service.init();
@@ -362,7 +365,8 @@ void loop()
 {
     uint32_t msecstosleep = 1000 * 30; // How long can we sleep before we again need to service the main loop?
 
-    gps->loop(); // FIXME, remove from main, instead block on read
+    if (gps)
+        gps->loop(); // FIXME, remove from main, instead block on read
     router.loop();
     powerFSM.run_machine();
     service.loop();

src/mesh/MeshService.cpp

@@ -67,8 +67,8 @@ void MeshService::init()
     sendOwnerPeriod.setup();
     nodeDB.init();
 
-    assert(gps);
-    gpsObserver.observe(&gps->newStatus);
+    if (gps)
+        gpsObserver.observe(&gps->newStatus);
     packetReceivedObserver.observe(&router.notifyPacketReceived);
 }