diff --git a/Makefile.extra b/Makefile.extra
index 0616171..e92ffec 100644
--- a/Makefile.extra
+++ b/Makefile.extra
@@ -1,6 +1,7 @@
 # -*- Makefile -*-
 # AUTOMAKE
 
+export AM_CFLAGS
 XA_SRCDIR = ${srcdir}
 XA_TOPSRCDIR = ${top_srcdir}
 XA_ABSTOPSRCDIR = ${abs_top_srcdir}
diff --git a/Makefile.iptrules.in b/Makefile.iptrules.in
index 53dbc92..b6b9fbe 100644
--- a/Makefile.iptrules.in
+++ b/Makefile.iptrules.in
@@ -13,10 +13,8 @@ CCLD            = ${CC}
 CFLAGS          = @CFLAGS@
 LDFLAGS         = @LDFLAGS@
 
-regular_CFLAGS  = @regular_CFLAGS@
 libxtables_CFLAGS = @libxtables_CFLAGS@
 libxtables_LIBS   = @libxtables_LIBS@
-AM_CFLAGS         = ${regular_CFLAGS} ${libxtables_CFLAGS} -I${abs_top_srcdir}/extensions
 AM_DEPFLAGS     = -Wp,-MMD,$(@D)/.$(@F).d,-MT,$@
 
 AM_DEFAULT_VERBOSITY = 0
diff --git a/extensions/Makefile.am b/extensions/Makefile.am
index 77153f3..9c9a095 100644
--- a/extensions/Makefile.am
+++ b/extensions/Makefile.am
@@ -1,6 +1,8 @@
 # -*- Makefile -*-
 # AUTOMAKE
 
+AM_CFLAGS = ${regular_CFLAGS} ${libxtables_CFLAGS} -I${abs_top_srcdir}/extensions
+
 # Not having Kbuild in Makefile.extra because it will already recurse
 .PHONY: modules modules_install clean_modules