Forgotten include guards.

Thanks again, KDevelop 5!

src/Magnum/Platform/ScreenedApplication.hpp

@@ -1,3 +1,5 @@
+#ifndef Magnum_Platform_ScreenedApplication_hpp
+#define Magnum_Platform_ScreenedApplication_hpp
 /*
     This file is part of Magnum.
 
@@ -141,3 +143,5 @@ template<class Application> void BasicScreenedApplication<Application>::mouseMov
 }
 
 }}
+
+#endif

src/Magnum/ResourceManager.hpp

@@ -1,3 +1,5 @@
+#ifndef Magnum_ResourceManager_hpp
+#define Magnum_ResourceManager_hpp
 /*
     This file is part of Magnum.
 
@@ -48,3 +50,5 @@ ResourceManager<Types...>*& ResourceManagerLocalInstanceImplementation<Types...>
 }
 
 }}
+
+#endif

src/Magnum/configure.h.cmake

@@ -1,3 +1,5 @@
+#ifndef Magnum_configure_h
+#define Magnum_configure_h
 /*
     This file is part of Magnum.
 
@@ -32,3 +34,5 @@
 #cmakedefine MAGNUM_TARGET_DESKTOP_GLES
 #cmakedefine MAGNUM_TARGET_WEBGL
 #cmakedefine MAGNUM_TARGET_HEADLESS
+
+#endif