--- a/src/sdlBasic/src/sdlBrt/SDLengine/SDLengine.h
+++ b/src/sdlBasic/src/sdlBrt/SDLengine/SDLengine.h
@@ -315,14 +315,14 @@
 void crossfadehandler(int s);
 int hit_pixelperfect(SDL_Surface *imga,int xa1,int ya1,int xa2,int ya2,SDL_Surface *imgb,int xb1,int yb1,int xb2,int yb2);
 
-Uint32(*getpixel)(SDL_Surface *surface, int x, int y);
+extern Uint32(*getpixel)(SDL_Surface *surface, int x, int y);
 Uint32 getpixel8(SDL_Surface *surface, int x, int y);
 Uint32 getpixel16(SDL_Surface *surface, int x, int y);
 Uint32 getpixel24BE(SDL_Surface *surface, int x, int y);
 Uint32 getpixel24(SDL_Surface *surface, int x, int y);
 Uint32 getpixel32(SDL_Surface *surface, int x, int y);
 
-void (*putpixel)(SDL_Surface *surface, int x, int y, Uint32 col );
+extern void (*putpixel)(SDL_Surface *surface, int x, int y, Uint32 col );
 void putpixel8(SDL_Surface *surface, int x, int y, Uint32 col );
 void putpixel16(SDL_Surface *surface, int x, int y, Uint32 col );
 void putpixel24BE(SDL_Surface *surface, int x, int y, Uint32 col );
@@ -337,7 +337,7 @@
 void draw_ellipse(SDL_Surface *surface,int vx,int vy,int Xradius,int Yradius,Uint32 color);
 void draw_fillellipse(SDL_Surface *surface,int vx,int vy,int Xradius,int Yradius,Uint32 color);
 
-Uint32 (*rrgb)(int col);
+extern Uint32 (*rrgb)(int col);
 Uint32 rrgb8(int col);
 Uint32 rrgb16(int col);
 Uint32 rrgb24(int col);
--- a/src/sdlBasic/src/sdlBrt/SDLengine/screen.c
+++ b/src/sdlBasic/src/sdlBrt/SDLengine/screen.c
@@ -28,6 +28,10 @@
 
 #include "SDLengine.h"
 
+Uint32(*getpixel)(SDL_Surface *surface, int x, int y);
+void (*putpixel)(SDL_Surface *surface, int x, int y, Uint32 col );
+Uint32 (*rrgb)(int col);
+
 //_________________________________________________________________________________________________________________________
 
 //SCREEN