diff --git a/tools/Makefile.inc b/tools/Makefile.inc
index cc25934eb..11f8c6a76 100644
--- a/tools/Makefile.inc
+++ b/tools/Makefile.inc
@@ -20,9 +20,11 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ###################################################################################
 
-ifeq ($(WITH_JSON),1)
+ifeq ($(WITH_CONFIG),1)
+ifeq ($(shell $(PKGCONFIG) libconfig; echo $$?),0)
 	TOOLS += $(BUILDDIR)/conf2json
 endif
+endif
 
 TOOLS_CFLAGS = $(CFLAGS)
 TOOLS_LDLIBS = -lconfig -ljansson -lvillas