Merge pull request #882 from ddovod/fixing_macro_redefined

Fixing 'GLM_ENABLE_EXPERIMENTAL macro redefined' warning #882

glm/detail/glm.cpp

@@ -1,7 +1,9 @@
 /// @ref core
 /// @file glm/glm.cpp
 
+#ifndef GLM_ENABLE_EXPERIMENTAL
 #define GLM_ENABLE_EXPERIMENTAL
+#endif
 #include <glm/gtx/dual_quaternion.hpp>
 #include <glm/gtc/vec1.hpp>
 #include <glm/gtc/quaternion.hpp>