SCons recipe: pass -D_X11 if X server headers are found.

SConstruct

@@ -170,10 +170,10 @@ if env["prereqs"]:
         conf.CheckSDL("SDL_image", require_version = '1.2.0') and \
         conf.CheckOgg() or Warning("Client prerequisites are not met. wesnoth, wesnoth_editor, cutter and exploder cannot be built.")
 
-    if env["PLATFORM"] == "win32":
-        have_X = True
-    else:
-        have_X = conf.CheckLib('X11') or Warning("wesnoth_editor cannot be built.")
+    have_X = False
+    if env["PLATFORM"] != "win32":
+        have_X = conf.CheckLib('X11')
+
     if env['fribidi']:
         env['fribidi'] = conf.CheckLibWithHeader('fribidi', 'fribidi/fribidi.h', 'C', 'fribidi_utf8_to_unicode(NULL,0,NULL);') or Warning("Can't find libfribidi, disabling freebidi support.")
 
@@ -246,6 +246,9 @@ if env['python']:
 if env['sendfile']:
     env.Append(CPPDEFINES = "USE_SENDFILE")
 
+if have_X:
+    env.Append(CPPDEFINES = "_X11")
+
 if sys.platform != "win32":
     if env['prefsdir']:
         env.Append(CPPDEFINES = "PREFERENCES_DIR='\"%s\"'" % env['prefsdir'] )
@@ -291,7 +294,7 @@ try:
 except:
     env["svnrev"] = ""
 
-Export(Split("env have_client_prereqs have_X have_server_prereqs"))
+Export(Split("env have_client_prereqs have_server_prereqs"))
 SConscript(dirs = Split("po doc packaging/windows"))
 
 binaries = Split("wesnoth wesnoth_editor wesnothd cutter exploder campaignd test")

src/SConscript

@@ -218,7 +218,7 @@ wesnoth_editor_sources = Split("""
     editor/editor_undo.cpp
     animated_editor.cpp
     """)
-if have_client_prereqs and have_X:
+if have_client_prereqs:
     wesnoth_editor = env.Program("wesnoth_editor", wesnoth_editor_sources + [libwesnoth_core, libwesnoth_sdl, libwesnoth] + wesnoth_editor_res)
 else:
     wesnoth_editor = None