Update GLM to latest version (0.9.9.3). This includes GLM's change of matrices no longer default initializing to the identity matrix. This commit thus also includes the update of all of LearnOpenGL's code to reflect this: all matrices are now constructor-initialized to the identity matrix where relevant.

includes/glm/ext/scalar_constants.hpp

@@ -0,0 +1,36 @@
+/// @ref ext_scalar_constants
+/// @file glm/ext/scalar_constants.hpp
+///
+/// @defgroup ext_scalar_constants GLM_EXT_scalar_constants
+/// @ingroup ext
+///
+/// Provides a list of constants and precomputed useful values.
+///
+/// Include <glm/ext/scalar_constants.hpp> to use the features of this extension.
+
+#pragma once
+
+// Dependencies
+#include "../detail/setup.hpp"
+
+#if GLM_MESSAGES == GLM_ENABLE && !defined(GLM_EXT_INCLUDED)
+#	pragma message("GLM: GLM_EXT_scalar_constants extension included")
+#endif
+
+namespace glm
+{
+	/// @addtogroup ext_scalar_constants
+	/// @{
+
+	/// Return the epsilon constant for floating point types.
+	template<typename genType>
+	GLM_FUNC_DECL GLM_CONSTEXPR genType epsilon();
+
+	/// Return the pi constant for floating point types.
+	template<typename genType>
+	GLM_FUNC_DECL GLM_CONSTEXPR genType pi();
+
+	/// @}
+} //namespace glm
+
+#include "scalar_constants.inl"