builddeb: Skip gcc-plugins when not configured

When attempting to build a Debian kernel package, the "scripts/gcc-plugins"
directory does not exist in the output tree unless CONFIG_GCC_PLUGINS=y.
To avoid errors when not defined, this wraps the failing "find" in a config
test.
Reported-by: Frank Paulsen <frobnic+lkml@gmail.com>
Tested-by: Christian Kujau <lists@nerdbynature.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michal Marek <mmarek@suse.com>

scripts/package/builddeb

@@ -332,7 +332,9 @@ if grep -q '^CONFIG_STACK_VALIDATION=y' $KCONFIG_CONFIG ; then
 	(cd $objtree; find tools/objtool -type f -executable) >> "$objtree/debian/hdrobjfiles"
 fi
 (cd $objtree; find arch/$SRCARCH/include Module.symvers include scripts -type f) >> "$objtree/debian/hdrobjfiles"
-(cd $objtree; find scripts/gcc-plugins -name \*.so -o -name gcc-common.h) >> "$objtree/debian/hdrobjfiles"
+if grep -q '^CONFIG_GCC_PLUGINS=y' $KCONFIG_CONFIG ; then
+	(cd $objtree; find scripts/gcc-plugins -name \*.so -o -name gcc-common.h) >> "$objtree/debian/hdrobjfiles"
+fi
 destdir=$kernel_headers_dir/usr/src/linux-headers-$version
 mkdir -p "$destdir"
 (cd $srctree; tar -c -f - -T -) < "$objtree/debian/hdrsrcfiles" | (cd $destdir; tar -xf -)