diff --git a/visualc/src/include/ngspice/config.h b/visualc/src/include/ngspice/config.h
index 31034f571..a3c6b90ed 100644
--- a/visualc/src/include/ngspice/config.h
+++ b/visualc/src/include/ngspice/config.h
@@ -551,3 +551,7 @@
 
 /* Define as `fork' if `vfork' does not work. */
 #define vfork fork
+
+#define HAVE_XFT
+
+#define EXT_ASC