Support spaces in Mac GN build output names.

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..c185ae17db5f9d67ef83b2cb837721aabc006ff5 100644
--- a/tools/gn/substitution_type.cc
+++ b/tools/gn/substitution_type.cc
@@ -22,6 +22,7 @@ const char* kSubstitutionNames[SUBSTITUTION_NUM_TYPES] = {
   "{{source_out_dir}}",  // SUBSTITUTION_SOURCE_OUT_DIR
 
   "{{label}}",  // SUBSTITUTION_LABEL
+  "{{label_name}}",  // SUBSTITUTION_LABEL_NAME
   "{{root_gen_dir}}",  // SUBSTITUTION_ROOT_GEN_DIR
   "{{root_out_dir}}",  // SUBSTITUTION_ROOT_OUT_DIR
   "{{target_gen_dir}}",  // SUBSTITUTION_TARGET_GEN_DIR
@@ -59,6 +60,7 @@ const char* kSubstitutionNinjaNames[SUBSTITUTION_NUM_TYPES] = {
     "source_out_dir",            // SUBSTITUTION_SOURCE_OUT_DIR
 
     "label",               // SUBSTITUTION_LABEL
+    "label_name",          // SUBSTITUTION_LABEL_NAME
     "root_gen_dir",        // SUBSTITUTION_ROOT_GEN_DIR
     "root_out_dir",        // SUBSTITUTION_ROOT_OUT_DIR
     "target_gen_dir",      // SUBSTITUTION_TARGET_GEN_DIR
@@ -124,6 +126,7 @@ bool IsValidToolSubstutition(SubstitutionType type) {
   return type == SUBSTITUTION_LITERAL ||
          type == SUBSTITUTION_OUTPUT ||
          type == SUBSTITUTION_LABEL ||
+         type == SUBSTITUTION_LABEL_NAME ||
          type == SUBSTITUTION_ROOT_GEN_DIR ||
          type == SUBSTITUTION_ROOT_OUT_DIR ||
          type == SUBSTITUTION_TARGET_GEN_DIR ||