Use a better check for support for std::unordered_map.

CMakeLists.txt

@@ -16,6 +16,15 @@ if (CMAKE_CXX_COMPILER MATCHES ".*clang")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-uninitialized")
 endif ()
 
+check_cxx_source_compiles(
+    "#include <unordered_map>
+     int main() {
+       std::unordered_map<int, int> m;
+       return 0;
+     }
+    "
+    USE_STD_UNORDERED_MAP)
+
 if (UNIX AND NOT APPLE)
   set(LINUX 1)
 endif (UNIX AND NOT APPLE)

src/config.h.in

@@ -43,5 +43,6 @@
 #cmakedefine IMOBILEDEVICE_USES_UDIDS
 #cmakedefine USE_INSTALL_PREFIX
 #cmakedefine USE_SYSTEM_PROJECTM
+#cmakedefine USE_STD_UNORDERED_MAP
 
 #endif // CONFIG_H_IN

src/playlist/playlist.cpp

@@ -64,15 +64,12 @@
 #include <algorithm>
 #include <boost/bind.hpp>
 
-#ifdef Q_OS_DARWIN
-  #include <tr1/unordered_map>
-
-  // I'm sorry...
-  namespace std {
-    using tr1::unordered_map;
-  }
-#else
+#ifdef USE_STD_UNORDERED_MAP
   #include <unordered_map>
+  using std::unordered_map;
+#else
+  #include <tr1/unordered_map>
+  using std::tr1::unordered_map;
 #endif
 
 using smart_playlists::Generator;
@@ -1944,7 +1941,7 @@ struct SongSimilarEqual {
 
 void Playlist::RemoveDuplicateSongs() {
   QList<int> rows_to_remove;
-  std::unordered_map<Song, int, SongSimilarHash, SongSimilarEqual> unique_songs;
+  unordered_map<Song, int, SongSimilarHash, SongSimilarEqual> unique_songs;
 
   for (int row = 0; row < items_.count(); ++row) {
     PlaylistItemPtr item = items_[row];