diff -uNr SDL-1.2.15/src/video/x11/SDL_x11sym.h SDL-1.2.15.mod/src/video/x11/SDL_x11sym.h
--- SDL-1.2.15/src/video/x11/SDL_x11sym.h	2012-01-19 08:30:06.000000000 +0200
+++ SDL-1.2.15.mod/src/video/x11/SDL_x11sym.h	2018-10-26 23:20:45.232058046 +0300
@@ -165,7 +165,7 @@
  */
 #ifdef LONG64
 SDL_X11_MODULE(IO_32BIT)
-SDL_X11_SYM(int,_XData32,(Display *dpy,register long *data,unsigned len),(dpy,data,len),return)
+SDL_X11_SYM(int,_XData32,(Display *dpy,register _Xconst long *data,unsigned len),(dpy,data,len),return)
 SDL_X11_SYM(void,_XRead32,(Display *dpy,register long *data,long len),(dpy,data,len),)
 #endif