diff --git a/lib/libc/libc_asm.mk b/lib/libc/libc_asm.mk
index 1597da4..e959687 100644
--- a/lib/libc/libc_asm.mk
+++ b/lib/libc/libc_asm.mk
@@ -26,6 +26,7 @@
 			strnlen.c			\
 			strrchr.c			\
 			strtok.c			\
+			strtoul.c			\
 			strtol.c)
 
 ifeq (${ARCH},aarch64)