Support script response files in GN.

tools/gn/substitution_type.cc

Index: tools/gn/substitution_type.cc
diff --git a/tools/gn/substitution_type.cc b/tools/gn/substitution_type.cc
index f67df262a21e80c6e39a41cdb3ae3f48c22a01f3..7862d1ee75fafb785b5cee1e4c3e4e9e5689a27b 100644
--- a/tools/gn/substitution_type.cc
+++ b/tools/gn/substitution_type.cc
@@ -43,6 +43,8 @@ const char* kSubstitutionNames[SUBSTITUTION_NUM_TYPES] = {
   "{{libs}}",  // SUBSTITUTION_LIBS
   "{{output_extension}}",  // SUBSTITUTION_OUTPUT_EXTENSION
   "{{solibs}}",  // SUBSTITUTION_SOLIBS
+
+  "{{response_file_name}}",  // SUBSTITUTION_RSP_FILE_NAME
 };
 
 const char* kSubstitutionNinjaNames[SUBSTITUTION_NUM_TYPES] = {
@@ -83,6 +85,8 @@ const char* kSubstitutionNinjaNames[SUBSTITUTION_NUM_TYPES] = {
     "libs",              // SUBSTITUTION_LIBS
     "output_extension",  // SUBSTITUTION_OUTPUT_EXTENSION
     "solibs",            // SUBSTITUTION_SOLIBS
+
+    "rspfile",  // SUBSTITUTION_RSP_FILE_NAME
 };
 
 SubstitutionBits::SubstitutionBits() : used() {