libc++ fixes: don't rely on tr1

libc++ doesn't ship tr1, but ships unordered_map as it is part of c++11.

Since this is the only tr1 header used in openmw, add a check for c++11
unordered_map and fallback to tr1 unordered_map if it's not found.

CMakeLists.txt

@@ -181,6 +181,12 @@ if (UNIX AND NOT APPLE)
     find_package (Threads)
 endif()
 
+include (CheckIncludeFileCXX)
+check_include_file_cxx(unordered_map HAVE_UNORDERED_MAP)
+if (HAVE_UNORDERED_MAP)
+    add_definitions(-DHAVE_UNORDERED_MAP)
+endif ()
+
 
 set(BOOST_COMPONENTS system filesystem program_options thread date_time wave)
 

components/files/configurationmanager.hpp

@@ -3,6 +3,8 @@
 
 #ifdef _WIN32
 #include <boost/tr1/tr1/unordered_map>
+#elif defined HAVE_UNORDERED_MAP
+#include <unordered_map>
 #else
 #include <tr1/unordered_map>
 #endif
@@ -48,7 +50,11 @@ struct ConfigurationManager
         typedef Files::FixedPath<> FixedPathType;
 
         typedef const boost::filesystem::path& (FixedPathType::*path_type_f)() const;
-        typedef std::tr1::unordered_map<std::string, path_type_f> TokensMappingContainer;
+	#if defined HAVE_UNORDERED_MAP
+            typedef std::unordered_map<std::string, path_type_f> TokensMappingContainer;
+	#else
+            typedef std::tr1::unordered_map<std::string, path_type_f> TokensMappingContainer;
+	#endif
 
         void loadConfig(const boost::filesystem::path& path,
             boost::program_options::variables_map& variables,