diff --git a/libsrc/include/Makefile.am b/libsrc/include/Makefile.am
index f84db193..c4420cf2 100644
--- a/libsrc/include/Makefile.am
+++ b/libsrc/include/Makefile.am
@@ -1,6 +1,7 @@
 noinst_HEADERS = acisgeom.hpp gprim.hpp meshing.hpp occgeom.hpp	\
 visual.hpp csg.hpp incvis.hpp myadt.hpp opti.hpp geometry2d.hpp	\
-linalg.hpp mydefs.hpp parallel.hpp stlgeom.hpp mystdlib.h
+linalg.hpp mydefs.hpp parallel.hpp stlgeom.hpp mystdlib.h	\
+nginterface_v2_impl.hpp
 
 include_HEADERS = nginterface.h nginterface_v2.hpp