NuttX debug jlink scripts minor improvements

- script return non-zero exit if there's a failure
 - upload script look for both gdb-multiarch and arm-none-eabi-gdb

platforms/nuttx/Debug/jlink_debug_gdb.sh.in

@@ -1,7 +1,5 @@
 #! /bin/sh
 
-set -o xtrace
-
 @JLinkGDBServerExe_PATH@ -device @DEBUG_DEVICE@ -select usb -endian little -if SWD -speed auto -ir -LocalhostOnly 1 -strict -vd -singlerun &
 
 cd @PX4_BINARY_DIR@ && @CMAKE_GDB@ -silent -nh \
@@ -12,3 +10,6 @@ cd @PX4_BINARY_DIR@ && @CMAKE_GDB@ -silent -nh \
 	-ex "monitor reset 0" \
 	-ex "continue" \
 	@PX4_CONFIG@.elf
+
+# exit with status of last command
+exit $?

platforms/nuttx/Debug/jlink_gdb_start.sh.in

@@ -1,7 +1,11 @@
 #! /bin/sh
 
-set -o xtrace
-
 killall JLinkGDBServerCLExe
 
-JLinkGDBServerCLExe -silent -device @DEBUG_DEVICE@ -select usb -if SWD -speed auto -LocalhostOnly 1 -strict -vd -singlerun &
+@JLinkGDBServerCLExe_PATH@ -silent -device @DEBUG_DEVICE@ -select usb -if SWD -speed auto -LocalhostOnly 1 -strict -vd -singlerun -timeout 3000 -powertarget 0 -nogui &
+sleep 2
+
+pgrep -i JLinkGDBServer
+
+# exit with status of last command
+exit $?

platforms/nuttx/Debug/upload_jlink_gdb.sh

@@ -1,14 +1,41 @@
 #! /bin/sh
 
-set -o xtrace
+if command -v gdb-multiarch &> /dev/null
+then
+	GDB_CMD=$(command -v gdb-multiarch)
 
-gdb-multiarch -silent -nx -batch \
-	-ex "target remote localhost:2331" \
-	-ex "monitor reset 0" \
-	-ex "load" \
-	-ex "monitor reset 0" \
-	-ex "monitor go" \
-	-ex "monitor sleep 3000" \
-	-ex "disconnect" \
-	-ex "quit" \
-	${1}
+elif command -v arm-none-eabi-gdb &> /dev/null
+then
+	GDB_CMD=$(command -v arm-none-eabi-gdb)
+
+else
+	echo "gdb arm-none-eabi or multi-arch not found"
+	exit 1
+fi
+
+file ${1}
+
+gdb_cmd_file=$(mktemp)
+
+cat >"${gdb_cmd_file}" <<EOL
+target remote localhost:2331
+monitor reset 0
+load
+monitor reset 0
+monitor go
+EOL
+
+for i in 1 2 3;
+do
+	${GDB_CMD} -silent --nh --nx --nw -batch -x ${gdb_cmd_file} ${1}
+	gdb_ret=$?
+
+	if [ $gdb_ret -ne 0 ]; then
+		echo "GDB error, retrying"
+		sleep 3
+	else
+		exit 0
+	fi
+done
+
+exit 1