Move dead submodules in-tree

Signed-off-by: swurl <swurl@swurl.xyz>

externals/oboe/samples/RhythmGame/third_party/glm/gtx/extend.hpp

@@ -0,0 +1,38 @@
+/// @ref gtx_extend
+/// @file glm/gtx/extend.hpp
+///
+/// @see core (dependence)
+///
+/// @defgroup gtx_extend GLM_GTX_extend
+/// @ingroup gtx
+///
+/// @brief Extend a position from a source to a position at a defined length.
+///
+/// <glm/gtx/extend.hpp> need to be included to use these functionalities.
+
+#pragma once
+
+// Dependency:
+#include "../glm.hpp"
+
+#if GLM_MESSAGES == GLM_MESSAGES_ENABLED && !defined(GLM_EXT_INCLUDED)
+#	pragma message("GLM: GLM_GTX_extend extension included")
+#endif
+
+namespace glm
+{
+	/// @addtogroup gtx_extend
+	/// @{
+
+	/// Extends of Length the Origin position using the (Source - Origin) direction.
+	/// @see gtx_extend
+	template <typename genType> 
+	GLM_FUNC_DECL genType extend(
+		genType const & Origin, 
+		genType const & Source, 
+		typename genType::value_type const Length);
+
+	/// @}
+}//namespace glm
+
+#include "extend.inl"