[wmlunits] Reset a reference early to keep less objects referenced...

...and enable (manual) GC. Should keep memory footprint below 500MB
now for the full WML tree of all addons on the 1.6 server.

data/tools/wmlunits

@@ -10,7 +10,7 @@ Run without arguments to see usage.
 try: import psyco; psyco.full()
 except ImportError: pass
 
-import sys, os, re, glob, shutil, copy, urllib2
+import sys, os, re, glob, shutil, copy, urllib2, gc
 
 import wesnoth.wmldata as wmldata
 import wesnoth.wmlparser as wmlparser
@@ -945,6 +945,8 @@ if __name__ == '__main__':
     global options
     global image_collector
     import optparse
+    
+    gc.disable()
 
     op = optparse.OptionParser()
     op.add_option("-l", "--language", default = "all",
@@ -1030,5 +1032,14 @@ if __name__ == '__main__':
             f = MyFile(os.path.join(options.output, "animations.html"), "w")
             animations.write_table(f, wesnoth)
             f.close()
-
-
+        
+        # Kill all references, this makes sure the reference counting
+        # kicks in and throws away all data for the previous
+        # translation - saving a bit of memory since otherwise two
+        # translations would be kept at a time.
+        wesnoth = None
+        
+        # We run a GC collection here, this ensures that also data
+        # which still are referenced but not reachable (yes, yes,
+        # this shouldn't happen) are freed.
+        gc.collect()