diff --git a/configure.ac b/configure.ac
index 8532bea6d..7c8e1803d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1297,6 +1297,7 @@ AC_CONFIG_FILES([Makefile
                  src/frontend/trannoise/Makefile
                  src/frontend/wdisp/Makefile
                  src/include/ngspice/Makefile
+                 src/include/cppduals/duals/Makefile
                  src/maths/Makefile
                  src/maths/cmaths/Makefile
                  src/maths/fft/Makefile
diff --git a/src/Makefile.am b/src/Makefile.am
index 826d0f90f..8ff6f7318 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,7 +1,7 @@
 ## Process this file with automake to produce Makefile.in
 
-SUBDIRS = include/ngspice misc maths frontend spicelib
-DIST_SUBDIRS = include/ngspice misc maths frontend spicelib xspice ciderlib
+SUBDIRS = include/ngspice include/cppduals/duals misc maths frontend spicelib
+DIST_SUBDIRS = include/ngspice include/cppduals/duals misc maths frontend spicelib xspice ciderlib
 
 if XSPICE_WANTED
 SUBDIRS += xspice