loader: const correctness

Author: rpavlik

src/loader/api_layer_interface.cpp

@@ -390,7 +390,7 @@ ApiLayerInterface::~ApiLayerInterface() {
     LoaderPlatformLibraryClose(_layer_library);
 }
 
-bool ApiLayerInterface::SupportsExtension(const std::string& extension_name) {
+bool ApiLayerInterface::SupportsExtension(const std::string& extension_name) const {
     bool found_prop = false;
     for (const std::string& supported_extension : _supported_extensions) {
         if (supported_extension == extension_name) {

src/loader/api_layer_interface.hpp

@@ -54,7 +54,7 @@ class ApiLayerInterface {
 
     // Generated methods
     void GenUpdateInstanceDispatchTable(XrInstance instance, std::unique_ptr<XrGeneratedDispatchTable>& table);
-    bool SupportsExtension(const std::string& extension_name);
+    bool SupportsExtension(const std::string& extension_name) const;
 
    private:
     std::string _layer_name;