diff --git a/makefiles/setup.mk b/makefiles/setup.mk
index e9da766c45..646846b253 100644
--- a/makefiles/setup.mk
+++ b/makefiles/setup.mk
@@ -33,6 +33,8 @@
 # Path and tool setup
 #
 
+export PX4_TARGET_OS 	 ?= nuttx
+
 # PX4_TARGET_OS	can be nuttx, linux, or qurt
 ifeq ($(PX4_TARGET_OS),)
 $(error Use: make PX4_TARGET_OS=<target> where <target> is nuttx, linux, or qurt)
diff --git a/src/drivers/rgbled/module.mk b/src/drivers/rgbled/module.mk
index 5ffa628c0d..a96480b38d 100644
--- a/src/drivers/rgbled/module.mk
+++ b/src/drivers/rgbled/module.mk
@@ -4,7 +4,7 @@
 
 MODULE_COMMAND	 = rgbled
 
-ifdef ($(PX4_TARGET_OS),nuttx)
+ifeq ($(PX4_TARGET_OS),nuttx)
 SRCS		 = rgbled.cpp
 else
 SRCS		 = rgbled_linux.cpp