minor build fixes and ignored warnings for GCC 9 (#14159)

- px4io task_main_trampoline add return
 - iridiumsbd main_loop_helper add return
 - drivers/uavcan ignore Wcast-align, Wdeprecated-copy, and Waddress-of-packed-member for now
 - flashparams ignore Wvla-larger-than
 - test_time fix printf type

src/drivers/px4io/px4io.cpp

@@ -303,7 +303,7 @@ private:
 	/**
 	 * Trampoline to the worker task
 	 */
-	static void		task_main_trampoline(int argc, char *argv[]);
+	static int		task_main_trampoline(int argc, char *argv[]);
 
 	/**
 	 * worker task
@@ -882,7 +882,7 @@ PX4IO::init()
 				   SCHED_DEFAULT,
 				   SCHED_PRIORITY_ACTUATOR_OUTPUTS,
 				   1500,
-				   (main_t)&PX4IO::task_main_trampoline,
+				   (px4_main_t)&PX4IO::task_main_trampoline,
 				   nullptr);
 
 	if (_task < 0) {
@@ -893,10 +893,11 @@ PX4IO::init()
 	return OK;
 }
 
-void
+int
 PX4IO::task_main_trampoline(int argc, char *argv[])
 {
 	g_dev->task_main();
+	return 0;
 }
 
 void

src/drivers/telemetry/iridiumsbd/IridiumSBD.cpp

@@ -213,7 +213,7 @@ int IridiumSBD::ioctl(struct file *filp, int cmd, unsigned long arg)
 // private functions                                                 //
 ///////////////////////////////////////////////////////////////////////
 
-void IridiumSBD::main_loop_helper(int argc, char *argv[])
+int IridiumSBD::main_loop_helper(int argc, char *argv[])
 {
 	// start the main loop and stay in it
 	IridiumSBD::instance->main_loop(argc, argv);
@@ -225,6 +225,7 @@ void IridiumSBD::main_loop_helper(int argc, char *argv[])
 	IridiumSBD::instance = nullptr;
 
 	PX4_WARN("stopped");
+	return 0;
 }
 
 void IridiumSBD::main_loop(int argc, char *argv[])

src/drivers/telemetry/iridiumsbd/IridiumSBD.h

@@ -139,7 +139,7 @@ private:
 	/*
 	 * Entry point of the task, has to be a static function
 	 */
-	static void main_loop_helper(int argc, char *argv[]);
+	static int main_loop_helper(int argc, char *argv[]);
 
 	/*
 	 * Main driver loop

src/drivers/uavcan/CMakeLists.txt

@@ -71,7 +71,11 @@ add_definitions(
 	-DUAVCAN_PLATFORM=${UAVCAN_PLATFORM}
 )
 
-add_compile_options(-Wno-cast-align) # TODO: fix and enable
+add_compile_options(
+	-Wno-cast-align # TODO: fix and enable
+	-Wno-deprecated-copy # TODO: fix
+	-Wno-address-of-packed-member
+)
 add_subdirectory(${LIBUAVCAN_DIR} libuavcan EXCLUDE_FROM_ALL)
 add_dependencies(uavcan prebuild_targets)