Properly ignore bdi_setup_and_register return value

This broke compilation against Linux 3.13 and GCC 4.7.3.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1906

diff --git a/config/kernel-bdi-setup-and-register.m4 b/config/kernel-bdi-setup-and-register.m4
index 4196091e91bea70a89ae63201715f075e786b46e..cb8ed67a19b30a66dc1f596bc736700d4b1eb302 100644 (file)
--- a/config/kernel-bdi-setup-and-register.m4
+++ b/config/kernel-bdi-setup-and-register.m4
@@ -1,12 +1,14 @@
 dnl #
 dnl # 2.6.34 API change
-dnl # The bdi_setup_and_register() helper function is avilable and
+dnl # The bdi_setup_and_register() helper function is available and
 dnl # exported by the kernel.  This is a trivial helper function but
 dnl # using it significantly simplifies the code surrounding setting
 dnl # up and tearing down the bdi structure.
 dnl #
 AC_DEFUN([ZFS_AC_KERNEL_BDI_SETUP_AND_REGISTER],
        [AC_MSG_CHECKING([whether bdi_setup_and_register() is available])
+       tmp_flags="$EXTRA_KCFLAGS"
+       EXTRA_KCFLAGS="-Wno-unused-result"
        ZFS_LINUX_TRY_COMPILE_SYMBOL([
                #include <linux/backing-dev.h>
        ], [
@@ -18,4 +20,5 @@ AC_DEFUN([ZFS_AC_KERNEL_BDI_SETUP_AND_REGISTER],
        ], [
                AC_MSG_RESULT(no)
        ])
+       EXTRA_KCFLAGS="$tmp_flags"
 ])