Initial work for GCC 4.5 compatibility.

GCC 4.5 doesn't know constexpr keyword and nullptr. As all constexpr
functions are here inline, it can be done with a simple macro.

CMakeLists.txt

@@ -3,6 +3,7 @@ cmake_minimum_required(VERSION 2.8.8)
 project(Magnum)
 
 option(TARGET_GLES "Build for OpenGL ES 2 instead of desktop OpenGL" OFF)
+option(GCC45_COMPATIBILITY "Enable compatibility mode for GCC 4.5 (might disable some features)" OFF)
 
 option(BUILD_TESTS "Build unit tests (requires Qt4)." OFF)
 

src/CMakeLists.txt

@@ -4,6 +4,10 @@ if(TARGET_GLES)
     set(MAGNUM_TARGET_GLES 1)
 endif()
 
+if(GCC45_COMPATIBILITY)
+    set(MAGNUM_GCC45_COMPATIBILITY 1)
+endif()
+
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/magnumConfigure.h.cmake
                ${CMAKE_CURRENT_BINARY_DIR}/magnumConfigure.h)
 

src/Math/Math.h

@@ -17,6 +17,7 @@
 
 #include <cstddef>
 
+#include "magnumCompatibility.h"
 #include "magnumVisibility.h"
 
 /** @file

src/Math/MathTypeTraits.h

@@ -21,6 +21,8 @@
 
 #include <cmath>
 
+#include "magnumCompatibility.h"
+
 /** @brief Precision when testing floats for equality */
 #ifndef FLOAT_EQUALITY_PRECISION
 #define FLOAT_EQUALITY_PRECISION 1.0e-6

src/magnumCompatibility.h

@@ -0,0 +1,25 @@
+#ifndef magnumCompatibility_h
+#define magnumCompatibility_h
+/*
+    Copyright © 2010, 2011, 2012 Vladimír Vondruš <mosra@centrum.cz>
+
+    This file is part of Magnum.
+
+    Magnum is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License version 3
+    only, as published by the Free Software Foundation.
+
+    Magnum is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+    GNU Lesser General Public License version 3 for more details.
+*/
+
+#include "magnumConfigure.h"
+
+#ifdef MAGNUM_GCC45_COMPATIBILITY
+#define constexpr
+#define nullptr 0
+#endif
+
+#endif

src/magnumConfigure.h.cmake

@@ -1 +1,2 @@
 #cmakedefine MAGNUM_TARGET_GLES
+#cmakedefine MAGNUM_GCC45_COMPATIBILITY