diff --git a/smc-command/Makefile b/smc-command/Makefile
index c78db24..9d532d8 100644
--- a/smc-command/Makefile
+++ b/smc-command/Makefile
@@ -1,5 +1,6 @@
 CC = gcc
 CFLAGS = -mmacosx-version-min=10.4  -Wall -g -framework IOKit
+CPPFLAGS = -DCMD_TOOL_BUILD
 
 all: smc 
 
@@ -7,7 +8,7 @@ smc: smc.o
 	$(CC) $(CFLAGS) -o smc smc.o
 
 smc.o: smc.h smc.c
-	$(CC) -c smc.c
+	$(CC) $(CPPFLAGS) -c smc.c
 
 clean:
 	-rm -f smc smc.o