buildroot

ccache: Patch to fix toolchain-wrapper's --sysroot

ccache doesn't rewrite the --sysroot base_dir from toolchain-wrapper
correctly. Resulting in a large number of cache misses when building
from different base directories.

A fix has already been accepted to the ccache upstream[1], but won't be
released until ccache 3.4. (Was noted as an improvement, so unsure
of the 3.4 release timing)

[1] https://github.com/ccache/ccache/pull/132

Signed-off-by: Brandon Maier <brandon.maier@rockwellcollins.com>
Signed-off-by: Matt Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>