otcl using tcl 8.6

diff --git a/Makefile.in b/Makefile.in
index 225fcdb..f97d3d6 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -9,6 +9,10 @@ CFLAGS=        @CFLAGS@
 RANLIB=    @RANLIB@
 INSTALL=   @INSTALL@

+# Compatibility with Tcl-8.6
+# See http://tmml.sourceforge.net/doc/tcl/CInterp.html
+CFLAGS+= -DUSE_INTERP_ERRORLINE -DUSE_INTERP_RESULT
+
 #
 # how to compile, link, and name shared libraries
 #