Switch to Subzero instead of LLVM on Linux.

Change-Id: Ib13af2fb929df98e0bb0e5af33a935942d854706
Reviewed-on: https://swiftshader-review.googlesource.com/9008
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
(cherry picked from commit 2aeaa6f445b1878a1ee3986c3b08ffa50323b366)
Reviewed-on: https://swiftshader-review.googlesource.com/9108
Reviewed-by: Alexis Hétu <sugoi@google.com>
diff --git a/src/Reactor/BUILD.gn b/src/Reactor/BUILD.gn
index 9495847..292b31f 100644
--- a/src/Reactor/BUILD.gn
+++ b/src/Reactor/BUILD.gn
@@ -15,7 +15,7 @@
 declare_args() {
   # Currently, Subzero is not used by default
   # LLVM is still the default backend
-  use_swiftshader_with_subzero = is_win
+  use_swiftshader_with_subzero = is_win || is_linux
 }
 
 # Need a separate config to ensure the warnings are added to the end.