Fix includes

src/celestia/celestiacore.h

@@ -29,6 +29,7 @@
 #include <celengine/viewporteffect.h>
 #include <celimage/pixelformat.h>
 #include <celutil/tee.h>
+#include "configfile.h"
 #include "favorites.h"
 #include "destination.h"
 #include "hud.h"

src/celestia/loadstars.cpp

@@ -9,9 +9,9 @@
 
 #include "loadstars.h"
 
-#include <filesystem>
 #include <fstream>
 
+#include <celcompat/filesystem.h>
 #include <celengine/stardb.h>
 #include <celestia/catalogloader.h>
 #include <celestia/configfile.h>