libsel4test: Add a dependency on libutils.

This is not currently used, but is to support an upcoming change.

libsel4test/Kbuild

diff --git a/libsel4test/Kbuild b/libsel4test/Kbuild
index c1d50ab..13e9f73 100644
--- a/libsel4test/Kbuild
+++ b/libsel4test/Kbuild
@@ -9,4 +9,4 @@
 #
 
 libs-$(CONFIG_LIB_SEL4_TEST) += libsel4test
-libsel4test: $(libc) libsel4 common
+libsel4test: $(libc) libsel4 common libutils

libsel4test/Kconfig

diff --git a/libsel4test/Kconfig b/libsel4test/Kconfig
index 4aea8f3..2f5a699 100644
--- a/libsel4test/Kconfig
+++ b/libsel4test/Kconfig
@@ -10,7 +10,7 @@
 
 menuconfig LIB_SEL4_TEST
     bool "libsel4test"
-    depends on HAVE_LIBC
+    depends on HAVE_LIBC && HAVE_LIB_UTILS
     select HAVE_LIB_SEL4_TEST
     default y
     help