add mqtt compile arg

backend/Makefile

@@ -4,7 +4,7 @@ MAKEFLAGS += -j16
 CXX=g++
 LD=g++
 
-CXXFLAGS = -std=c++23 -pedantic-errors -Wall -Wextra -Wconversion -ftemplate-backtrace-limit=0
+CXXFLAGS = -std=c++23 -pedantic-errors -Wall -Wextra -Wconversion
 LDFLAGS =
 
 libraries = libmosquitto
@@ -30,6 +30,11 @@ ifeq ($(ASAN),1)
 	CXXFLAGS += -fsanitize=address
 endif
 
+MQTT_HOST=
+ifneq ($(MQTT_HOST),)
+	CXXFLAGS += -DBACKEND_MQTT_HOST=\"$(MQTT_HOST)\"
+endif
+
 build_dir = build
 obj_dir = $(build_dir)/obj
 src_dir = src

backend/src/main.cpp

@@ -23,10 +23,15 @@
 #define BACKEND_MQTT_PORT 1883
 #endif
 
+#ifndef BACKEND_MQTT_HOST
+#define BACKEND_MQTT_HOST "mosquitto"
+#endif
+
 int main(void)
 {
-    auto mqtt_client
-        = mst::mqtt::Client("10.133.51.127", BACKEND_MQTT_PORT, "test", "1234");
+
+    auto mqtt_client = mst::mqtt::Client(
+        BACKEND_MQTT_HOST, BACKEND_MQTT_PORT, "test", "1234");
 
     mqtt_client.subscribe("/skateboard/update", [&](std::string_view text) {
         //