diff --git a/tools/cpp/CROSSTOOL b/tools/cpp/CROSSTOOL
index 342cc66..2390000 100644
--- a/tools/cpp/CROSSTOOL
+++ b/tools/cpp/CROSSTOOL
@@ -156,6 +156,15 @@
       flag_group {
         flag: "-std=gnu++11"
       }
+    }
+    flag_set {
+      action: "preprocess-assemble"
+      action: "c-compile"
+      action: "c++-compile"
+      action: "c++-header-parsing"
+      action: "c++-header-preprocessing"
+      action: "c++-module-compile"
+      flag_group {
 	  flag_group {
         # We always want to compile with -pthread semantics.
 	    flag: "-pthread"