FIX: extern declaration for non-static variable default_resource_search_paths for cpplint

library/phx/resources/resource_utils.cpp

@@ -34,6 +34,14 @@
 #include "phx/resources_path.hpp"
 
 namespace phx {
+namespace {
+std::vector<std::string> default_resource_search_paths = {
+    {std::string("./"), resources_root}};
+}
+
+std::vector<std::string> ResourceUtils::resource_search_paths_{
+    default_resource_search_paths};
+
 ResourceDeclaration ResourceUtils::GenericMaterialDeclaration(
     const std::string& material_name, glm::vec3 diffuse_color,
     glm::vec3 specular_color, glm::vec3 ambient_color, float shininess) {
@@ -50,12 +58,6 @@ ResourceDeclaration ResourceUtils::GenericMaterialDeclaration(
   return declaration;
 }
 
-std::vector<std::string> default_resource_search_paths = {
-    {std::string("./"), resources_root}};
-
-std::vector<std::string> ResourceUtils::resource_search_paths_{
-    default_resource_search_paths};
-
 void ResourceUtils::AddResourceSearchPath(const std::string& path_to_add) {
   assert(!path_to_add.empty());
   auto p = (path_to_add.back() == '/' ? path_to_add