- Rename structs folder to struct

- Include files in `cglms.h`
- Fix style issues (tabs to spaces, open brace without newline)

include/cglm/struct/color.h

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c), Recep Aslantas.
+ *
+ * MIT License (MIT), http://opensource.org/licenses/MIT
+ * Full license can be found in the LICENSE file
+ */
+
+#ifndef cglm_colors_h
+#define cglm_colors_h
+
+#include "../common.h"
+#include "../types-struct.h"
+#include "../color.h"
+#include "vec3.h"
+
+/*!
+ * @brief averages the color channels into one value
+ *
+ * @param[in]  rgb RGB color
+ */
+CGLM_INLINE
+float
+glms_luminance(vec3s rgb) {
+  return glm_luminance(rgb.raw);
+}
+
+#endif /* cglm_colors_h */