diff --git a/gnu/lib/Makefile b/gnu/lib/Makefile
index 796cefcacc98..abcb0e277d33 100644
--- a/gnu/lib/Makefile
+++ b/gnu/lib/Makefile
@@ -16,7 +16,7 @@ SUBDIR+= libssp
 SUBDIR+= tests
 .endif
 
-.if ${MK_GDB} != "no"
+.if ${MK_GDB} != "no" || ${MK_NTP} != "no"
 SUBDIR+=	libreadline
 .endif