diff --git a/adm_local/unix/config_files/check_Netgen.m4 b/adm_local/unix/config_files/check_Netgen.m4
index 8366e56ec..971477c3d 100644
--- a/adm_local/unix/config_files/check_Netgen.m4
+++ b/adm_local/unix/config_files/check_Netgen.m4
@@ -113,7 +113,7 @@ else
   NETGEN_LIBS="-lNETGEN"
   CPPFLAGS="${CPPFLAGS} -DHAVE_NETGEN"
   IDLCXXFLAGS="${IDLCXXFLAGS} -DHAVE_NETGEN"
-  IDLPYFLAGS="${IDLPYFLAGS} -DHAVE_NETGEN"
+  OMNIORB_IDLPYFLAGS="${OMNIORB_IDLPYFLAGS} -DHAVE_NETGEN"
 fi
 fi
 AC_SUBST(NETGEN_INCLUDES)