From bb5cc9cee1963362fe56b4fac65fed4912da4215 Mon Sep 17 00:00:00 2001
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Date: Sat, 30 Jul 2016 22:30:01 +0200
Subject: [PATCH] configure: add cache variable for Linux proc filesystem check

When cross-compiling, whether the /proc filesystem is available in the
build environment does not give any indication as to whether it will
be available in the execution environment.

This commit therefore adjust the AF_LINUX_PROCFS macro to use
AC_CACHE_CHECK(), so that an ac_cv_linux_procfs variable can be
preseeded in the environment to force the result of this check.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 aclocal.m4 | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/aclocal.m4 b/aclocal.m4
index 2115204..333699c 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -80,16 +80,11 @@ dnl
 dnl Check for the Linux /proc filesystem
 dnl --------------------------------------------------------------------------
 AC_DEFUN(AF_LINUX_PROCFS,
-[AC_MSG_CHECKING(for Linux proc filesystem)
-if test "x`cat /proc/sys/kernel/ostype 2>&-`" = "xLinux"
-then
-	linux_procfs=yes
-else
-	linux_procfs=no
-fi
-AC_MSG_RESULT($linux_procfs)
-if test $linux_procfs = yes
-then
+[AC_CACHE_CHECK([for Linux proc filesystem], [ac_cv_linux_procfs],
+	[ac_cv_linux_procfs=no
+	 test "x`cat /proc/sys/kernel/ostype 2>&-`" = "xLinux" && ac_cv_linux_procfs=yes])
+ if test $ac_cv_linux_procfs = yes
+ then
 	AC_DEFINE(HAVE_LINUX_PROCFS, 1,
 		[Define if you have the Linux /proc filesystem.])
 fi])
-- 
2.7.4