Update code style

Limit source code to 80 chars, and declare functions return type and
modifiers on a separate line.

This allows to avoid very long lines, and all function names are
aligned.

(We do this on VLC, and I like it.)

app/src/screen.h

@@ -38,36 +38,44 @@ struct screen {
 }
 
 // init SDL and set appropriate hints
-SDL_bool sdl_init_and_configure(void);
+SDL_bool
+sdl_init_and_configure(void);
 
 // initialize default values
-void screen_init(struct screen *screen);
+void
+screen_init(struct screen *screen);
 
 // initialize screen, create window, renderer and texture (window is hidden)
-SDL_bool screen_init_rendering(struct screen *screen,
-                               const char *device_name,
-                               struct size frame_size,
-                               SDL_bool always_on_top);
+SDL_bool
+screen_init_rendering(struct screen *screen, const char *device_name,
+                      struct size frame_size, SDL_bool always_on_top);
 
 // show the window
-void screen_show_window(struct screen *screen);
+void
+screen_show_window(struct screen *screen);
 
 // destroy window, renderer and texture (if any)
-void screen_destroy(struct screen *screen);
+void
+screen_destroy(struct screen *screen);
 
 // resize if necessary and write the rendered frame into the texture
-SDL_bool screen_update_frame(struct screen *screen, struct video_buffer *vb);
+SDL_bool
+screen_update_frame(struct screen *screen, struct video_buffer *vb);
 
 // render the texture to the renderer
-void screen_render(struct screen *screen);
+void
+screen_render(struct screen *screen);
 
 // switch the fullscreen mode
-void screen_switch_fullscreen(struct screen *screen);
+void
+screen_switch_fullscreen(struct screen *screen);
 
 // resize window to optimal size (remove black borders)
-void screen_resize_to_fit(struct screen *screen);
+void
+screen_resize_to_fit(struct screen *screen);
 
 // resize window to 1:1 (pixel-perfect)
-void screen_resize_to_pixel_perfect(struct screen *screen);
+void
+screen_resize_to_pixel_perfect(struct screen *screen);
 
 #endif