[U-Boot] Cannot build Wandboard SPL

[Heinrich Schuchardt]

make mrproper
make wandboard_defconfig
make SPL

leads to an error

   OBJCOPY spl/u-boot-spl-nodtb.bin
   COPY    spl/u-boot-spl.bin
   CFGS    .cfgtmp
gcc: error: FORCE: Datei oder Verzeichnis nicht gefunden
gcc: warning: ‘-x c’ after last input file has no effect
gcc: fatal error: no input files
compilation terminated.

Bisection leads to this patch:

commit 6e6cf015e7cdd7ca83a933320a81201972bd5e5e
Merge: 0931b6f20e 5451ca4da9
Author: Tom Rini <trini at konsulko.com>
Date:   Mon Nov 27 07:22:11 2017 -0500

     Merge git://www.denx.de/git/u-boot-imx

     Signed-off-by: Tom Rini <trini at konsulko.com>

My build-system is a Wandboad Quad with Debian Stretch
gcc (Debian 6.3.0-18) 6.3.0 20170516

Best regards

Heinrich Schuchardt