Setup inotify to watch for modifications of buffer source files

src/renderer.h

@@ -9,6 +9,7 @@
 struct shader_state {
   unsigned int program; /**< Shader program ID. */
   const char *filename; /**< Shader file name. */
+  int wd;               /**< inotify watch descriptor. */
 };
 
 /**
@@ -19,9 +20,10 @@ struct renderer_state {
   GLFWwindow *window; /**< GLFW window where the shaders are rendered. */
   struct shader_state screen_shader; /**< Shader for the main screen. */
   struct shader_state buffer_shader; /**< Shader for the framebuffer. */
+  int inotify_fd;                    /**< inotify file descriptor. */
   size_t frame_count; /**< Frame count since the start of the render loop. */
   size_t prev_frame_count; /**< Frame count at the last log. */
-  double time; /**< Time in seconds since the beginning of the render loop. */
+  double time;      /**< Time in seconds since the start of the render loop. */
   double prev_time; /**< Time in seconds at the last log. */
 };