diff --git a/service/spkg/Makefile b/service/spkg/Makefile
index 3943d96..9859ca4 100644
--- a/service/spkg/Makefile
+++ b/service/spkg/Makefile
@@ -12,9 +12,10 @@ CFILES = $(shell find . -name "*.c")
 OFILES = $(CFILES:.c=.o)
 DFILES = $(CFILES:.c=.d)
 
-CFLAGS = 					\
-	$(SYS_CFLAGS)			\
-	-MMD					\
+CFLAGS = 								   \
+	$(SYS_CFLAGS)						   \
+	-MMD								   \
+	-I$(PT_PROJECT_ROOT)/service/spkg/head \
 	-I$(PT_PROJECT_ROOT)/sdk/head
 
 .PHONY: all
diff --git a/service/spkg/strlib/strlen.c b/service/spkg/strlib/strlen.c
index 0045354..3029d89 100644
--- a/service/spkg/strlib/strlen.c
+++ b/service/spkg/strlib/strlen.c
@@ -7,6 +7,7 @@
  */
 
 #include <ptdef.h>
+#include <string.h>
 
 USIZE
 RtlStrLen(const CHAR *String)