wine: fix sane related build failure

If sane is installed system-wide on the build machine, then the
sane-config binary found is the one of the system, which returns
incorrect library paths for cross-compilation.

To fix this, this commit adds a patch to wine to make it support a
SANE_CONFIG environment variable, and then adjusts wine.mk to
explicitly pass the path to $(STAGING_DIR)/usr/bin/sane-config.

Fixes:

  http://autobuild.buildroot.org/results/8bd/8bdc1eed55075313403aa8a6c9af6a427bce198e/



Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>