Update _XData32 declaration in SDL_x11sym.h to match that of libx11 1.6.

--- SDL-1.2.15/src/video/x11/SDL_x11sym.h.~1~	2012-01-19 01:30:06.000000000 -0500
+++ SDL-1.2.15/src/video/x11/SDL_x11sym.h	2014-12-26 00:22:36.445067694 -0500
@@ -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
 
rm'><form method='get'>
<input type='hidden' name='id' value='de261ace27d5fb349cc614e0370bf07ca390becd'/><select name='h' onchange='this.form.submit();'>
<option value='koszko' selected='selected'>koszko</option>
<option value='koszko-scripts'>koszko-scripts</option>
</select> <input type='submit' value='switch'/></form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=de261ace27d5fb349cc614e0370bf07ca390becd'>refs</a><a class='active' href='/guix/log/nix/scripts/authenticate.in'>log</a><a href='/guix/tree/nix/scripts/authenticate.in?id=de261ace27d5fb349cc614e0370bf07ca390becd'>tree</a><a href='/guix/commit/nix/scripts/authenticate.in?id=de261ace27d5fb349cc614e0370bf07ca390becd'>commit</a><a href='/guix/diff/nix/scripts/authenticate.in?id=de261ace27d5fb349cc614e0370bf07ca390becd'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/nix/scripts/authenticate.in'>
<input type='hidden' name='id' value='de261ace27d5fb349cc614e0370bf07ca390becd'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=de261ace27d5fb349cc614e0370bf07ca390becd'>root</a>/<a href='/guix/log/nix?id=de261ace27d5fb349cc614e0370bf07ca390becd'>nix</a>/<a href='/guix/log/nix/scripts?id=de261ace27d5fb349cc614e0370bf07ca390becd'>scripts</a>/<a href='/guix/log/nix/scripts/authenticate.in?id=de261ace27d5fb349cc614e0370bf07ca390becd'>authenticate.in</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/nix/scripts/authenticate.in?id=de261ace27d5fb349cc614e0370bf07ca390becd&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2018-11-14 21:34:08 +0100'>2018-11-14</span></td><td><a href='/guix/commit/nix/scripts/authenticate.in?id=0fe1fba4af41f267c4bb2c006fb37f42422ab703'>daemon: Install 'authenticate' script under LIBEXECDIR/guix.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>