diff --git a/avl/Makefile.am b/avl/Makefile.am
index 2e935a4..516a191 100644
--- a/avl/Makefile.am
+++ b/avl/Makefile.am
@@ -10,7 +10,7 @@ noinst_HEADERS = avl.h
 libiceavl_la_SOURCES = avl.c
 libiceavl_la_CFLAGS = @XIPH_CFLAGS@
 
-INCLUDES = -I$(srcdir)/..
+AM_CPPFLAGS = -I$(srcdir)/..
 
 debug:
 	$(MAKE) all CFLAGS="@DEBUG@"
diff --git a/httpp/Makefile.am b/httpp/Makefile.am
index 11989e0..8ddb930 100644
--- a/httpp/Makefile.am
+++ b/httpp/Makefile.am
@@ -7,9 +7,7 @@ noinst_HEADERS = httpp.h encoding.h
 
 libicehttpp_la_SOURCES = httpp.c encoding.c
 libicehttpp_la_CFLAGS = @XIPH_CFLAGS@
-AM_CPPFLAGS = @XIPH_CPPFLAGS@
-
-INCLUDES = -I$(srcdir)/..
+AM_CPPFLAGS = -I$(srcdir)/.. @XIPH_CPPFLAGS@
 
 # SCCS stuff (for BitKeeper)
 GET = true
diff --git a/net/Makefile.am b/net/Makefile.am
index 0747825..870e800 100644
--- a/net/Makefile.am
+++ b/net/Makefile.am
@@ -10,7 +10,7 @@ noinst_HEADERS = resolver.h sock.h
 libicenet_la_SOURCES = sock.c resolver.c
 libicenet_la_CFLAGS = @XIPH_CFLAGS@
 
-INCLUDES = -I$(srcdir)/..
+AM_CPPFLAGS = -I$(srcdir)/..
 
 debug:
 	$(MAKE) all CFLAGS="@DEBUG@"
diff --git a/thread/Makefile.am b/thread/Makefile.am
index 5651a1b..0109a49 100644
--- a/thread/Makefile.am
+++ b/thread/Makefile.am
@@ -10,7 +10,7 @@ noinst_HEADERS = thread.h
 libicethread_la_SOURCES = thread.c
 libicethread_la_CFLAGS = @XIPH_CFLAGS@
 
-INCLUDES = -I$(srcdir)/..
+AM_CPPFLAGS = -I$(srcdir)/..
 
 debug:
 	$(MAKE) all CFLAGS="@DEBUG@"