scons/windows: Fix build with LLVM>=8

Fixes eebe091d292609de8aaf5b5c537d867b23908947
("scons/windows: Enable compute shaders when possible.")
Signed-off-by: Prodea Alexandru-Liviu <liviuprodea@yahoo.com>
Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
1 file changed