diff --git a/src/system/kernel/lib/Jamfile b/src/system/kernel/lib/Jamfile
index 78c92cc060..cd831f15b4 100644
--- a/src/system/kernel/lib/Jamfile
+++ b/src/system/kernel/lib/Jamfile
@@ -84,6 +84,7 @@ KernelMergeObject kernel_lib_posix.o :
 	usergroup.cpp
 	write.c
 	# string
+	ffs.cpp
 	memchr.c
 	memcmp.c
 	memmove.c