sent upstream:
https://lists.alioth.debian.org/pipermail/sane-devel/2015-July/033600.html

From c8df148e2b9784be1827e33224baa1cb5066a383 Mon Sep 17 00:00:00 2001
From: Mike Frysinger <vapier@chromium.org>
Date: Wed, 8 Jul 2015 06:31:12 -0400
Subject: [PATCH] fix cross-compiling paths

There's no reason to hardcode -I paths to /usr/local.  Doing so breaks
cross-compiling when incompatible headers live in there or the toolchain
is set up to throw errors with those flags.
---
 configure.in | 1 -
 1 file changed, 1 deletion(-)

diff --git a/configure.in b/configure.in
index 48953d2..059058b 100644
--- a/configure.in
+++ b/configure.in
@@ -82,7 +82,6 @@ AM_CONDITIONAL(CROSS_COMPILING, test x$cross_compiling = xyes)
 dnl ***********************************************************************
 dnl set compiler/linker flags
 dnl ***********************************************************************
-INCLUDES="${INCLUDES} -I/usr/local/include"
 AC_SUBST(INCLUDES)
 SANE_SET_CFLAGS([$is_release])
 SANE_SET_LDFLAGS
-- 
2.4.4