GCC 4.6 compatibility: no user-defined literals.

src/Magnum.h

@@ -40,10 +40,12 @@ namespace Magnum {
 namespace Math {
     template<class T> struct Constants;
 
+    #ifndef CORRADE_GCC46_COMPATIBILITY
     constexpr Rad<Double> operator "" _rad(long double);
     constexpr Rad<Float> operator "" _radf(long double);
     constexpr Deg<Double> operator "" _deg(long double);
     constexpr Deg<Float> operator "" _degf(long double);
+    #endif
 }
 
 /* Bring debugging facility from Corrade::Utility namespace */
@@ -240,11 +242,13 @@ typedef Math::Geometry::Rectangle<Double> Rectangled;
 /*@}*/
 #endif
 
+#ifndef CORRADE_GCC46_COMPATIBILITY
 /* Using angle literals from Math namespace */
 using Math::operator "" _deg;
 using Math::operator "" _degf;
 using Math::operator "" _rad;
 using Math::operator "" _radf;
+#endif
 
 /** @todoc Remove `ifndef` when Doxygen is sane again */
 #ifndef DOXYGEN_GENERATING_OUTPUT

src/Math/Angle.h

@@ -20,6 +20,7 @@
  */
 
 #include <Utility/Debug.h>
+#include <corradeCompatibility.h>
 
 #include "Math/Constants.h"
 #include "Math/Math.h"

src/Math/Test/AngleTest.cpp

@@ -73,6 +73,7 @@ void AngleTest::construct() {
 }
 
 void AngleTest::literals() {
+    #ifndef CORRADE_GCC46_COMPATIBILITY
     constexpr auto a = 25.0_deg;
     constexpr auto b = 25.0_degf;
     CORRADE_VERIFY((std::is_same<decltype(a), const Degd>::value));
@@ -86,6 +87,9 @@ void AngleTest::literals() {
     CORRADE_VERIFY((std::is_same<decltype(n), const Rad>::value));
     CORRADE_COMPARE(Double(m), 3.14);
     CORRADE_COMPARE(Float(n), 3.14f);
+    #else
+    CORRADE_SKIP("User-defined literals are not available on GCC < 4.7.");
+    #endif
 }
 
 void AngleTest::conversion() {