diff --git a/config/am_include.mk b/config/am_include.mk
index a0af316..feb0195 100644
--- a/config/am_include.mk
+++ b/config/am_include.mk
@@ -22,13 +22,7 @@
 ## It is actually included when a makefile.am is coverted to Makefile.in
 ## by automake, so it's ok to have @MACROS@ that will be set by configure
 
-
-## INCLUDES is automatically added to CXXFLAGS at compile time. The
-## $(top_srcdir) macro is set by configure. It's important to use $(top_srcdir)
-## in case a user decides to build in a separate directory from the base package
-## directory. Using absolute, or relative paths is a bad idea.
-INCLUDES=-I$(top_srcdir)/include
-
+AM_CPPFLAGS=-I$(top_srcdir)/include
 
 # doc directory
 pkgdocdir=$(prefix)/doc/@PACKAGE@