cross-compile bind9 failing - rndc linking error

Cross-compiling bind 9.18.28 fails while linking rndc. Following simple patch fixes it:

diff --git a/bin/rndc/Makefile.am b/bin/rndc/Makefile.am
index a668522bc2..77071e7569 100644
--- a/bin/rndc/Makefile.am
+++ b/bin/rndc/Makefile.am
@@ -2,6 +2,7 @@ include $(top_srcdir)/Makefile.top
 
 AM_CPPFLAGS +=                 \
        $(LIBISC_CFLAGS)        \
+       $(LIBNS_CFLAGS)         \
        $(LIBDNS_CFLAGS)        \
        $(LIBISCCFG_CFLAGS)     \
        $(LIBISCCC_CFLAGS)      \
@@ -20,6 +21,7 @@ rndc_SOURCES =        \
 
 rndc_LDADD =                   \
        $(LIBISC_LIBS)          \
+       $(LIBNS_LIBS)           \
        $(LIBDNS_LIBS)          \
        $(LIBISCCC_LIBS)        \
        $(LIBISCCFG_LIBS)       \

Thanks in advance for fixing it upstream.