diff --git a/tools/gn/config_values.cc b/tools/gn/config_values.cc
index d87ed84..73486cd 100644
--- a/tools/gn/config_values.cc
+++ b/tools/gn/config_values.cc
@@ -23,6 +23,7 @@
 }
 
 void ConfigValues::AppendValues(const ConfigValues& append) {
+  VectorAppend(&asmflags_,     append.asmflags_);
   VectorAppend(&cflags_,       append.cflags_);
   VectorAppend(&cflags_c_,     append.cflags_c_);
   VectorAppend(&cflags_cc_,    append.cflags_cc_);