Android: Default to toolchain version 4.8 on Windows as well

The default has already been changed in the configure shell script,
but configure.exe needs the same change to be compatible with the
current NDK (which no longer contains the 4.7 toolchain)

Change-Id: Icd6474c3c9b9bbefbba5a1273a466c7ff099b7e0
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>