scripts/update-linux-headers: Handle kernel license no longer being one file

The kernel has changed its license documentation, so instead of COPYING
being a stand-alone file that defines the license, it refers to various
other files under LICENSES/. This means we need to copy not just COPYING
but also these other files to our copy of the kernel headers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20180525132755.21839-4-peter.maydell@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

scripts/update-linux-headers.sh

@@ -142,6 +142,20 @@ else
     cp "$linux/COPYING" "$output/linux-headers"
 fi
 
+# Recent kernel sources split the copyright/license info into multiple
+# files, which we need to copy. This set of licenses is the set that
+# are referred to by SPDX lines in the headers we currently copy.
+# We don't copy the Documentation/process/license-rules.rst which
+# is also referred to by COPYING, since it's explanatory rather than license.
+if [ -d "$linux/LICENSES" ]; then
+    mkdir -p "$output/linux-headers/LICENSES/preferred" \
+             "$output/linux-headers/LICENSES/exceptions"
+    for l in preferred/GPL-2.0 preferred/BSD-2-Clause preferred/BSD-3-Clause \
+             exceptions/Linux-syscall-note; do
+        cp "$linux/LICENSES/$l" "$output/linux-headers/LICENSES/$l"
+    done
+fi
+
 cat <<EOF >$output/linux-headers/linux/virtio_config.h
 #include "standard-headers/linux/virtio_config.h"
 EOF