Add option to enable SVN revision display, defaulting to off.

INSTALL

@@ -55,6 +55,11 @@ you have a Subversion client installed but it is not implementing the
 If you want to build wesnoth_editor too add the --enable-editor
 configure option.
 
+The --display-revision option enables code that shows the SVN revision
+number on the main screen -- useful for detecting old builds you might
+happen to have in your path, but probably not what you want in a 
+production release.
+
 In case you want wesnothd to be built you should add:
 --enable-server --localstatedir=/var --with-server-uid=user
 --with-server-gid=group

configure.ac

@@ -237,6 +237,11 @@ AC_ARG_ENABLE([internal-data],
 		[internaldata=$enableval],
 		[internaldata=no])
 
+AC_ARG_ENABLE([display-revision],
+              AS_HELP_STRING([--display-revisiion], [enable svn revision display]),
+	      [svnrev=$enableval],
+	      [svnrev=no])
+
 AM_CONDITIONAL([STATIC], [test x$static = xyes])
 AM_CONDITIONAL([GAME], [test x$game = xyes])
 AM_CONDITIONAL([SERVER], [test x$server = xyes])
@@ -256,6 +261,10 @@ if test x$internaldata = xyes; then
   AC_DEFINE([USE_INTERNAL_DATA],[],[Define if translations should be placed inside app, for Mac OS X])
 fi
 
+if test x$svnrev = xyes; then
+  AC_DEFINE([DO_DISPLAY_REVISION],[],[Define if SVN revision should be displayed when querying the version])
+fi
+
 AC_ARG_ENABLE([desktop-entry],
               AS_HELP_STRING([--disable-desktop-entry], [disable installation of desktop entry files]),
 	      [desktopentry=$enableval],

src/editor/editor_main.cpp

@@ -67,9 +67,9 @@ int main(int argc, char** argv)
 		} else if(val == "--version" || val == "-v") {
 			std::cout << "Battle for Wesnoth " 
 				  << game_config::version
-#ifdef SVNREV
+#if defined(SVNREV) and defined(DO_DISPLAY_REVISION)
 				  << " (" << game_config::svnrev << ")"
-#endif /* SVNREV */
+#endif /* defined(SVNREV) and defined(DO_DISPLAY_REVISION) */
 			          << "\n";
 			return 0;
 		} else if(val == "--path") {

src/titlescreen.cpp

@@ -232,9 +232,9 @@ TITLE_RESULT show_title(display& screen, config& tips_of_day, int* ntip)
 
 	const std::string& version_str = _("Version") + std::string(" ") +
 		game_config::version
-#ifdef SVNREV
+#if defined(SVNREV) and defined(DO_DISPLAY_REVISION)
        		+ " (" + game_config::svnrev + ")"
-#endif /* SVNREV */
+#endif /* defined(SVNREV) and defined(DO_DISPLAY_REVISION) */
        	;
 
 	const SDL_Rect version_area = font::draw_text(NULL,screen_area(),