Refuse to run if the last bit of the destination path contains a # character.
This is a silly workaround for a rather serious bug in MacOSX: if you take
a long filename and convert it to an FSSpec the fsspec gets a magic
cooky (containing a #, indeed). If you then massage the extension of this
fsspec and convert back to a pathname you may end up referring to the
same file. This could destroy your sourcefile. The problem only occcurs
in MacPython-OS9, not MacPython-OSX (I think).

Closes bug #505562.
diff --git a/Mac/Lib/buildtools.py b/Mac/Lib/buildtools.py
index ca9b252..a5e641d 100644
--- a/Mac/Lib/buildtools.py
+++ b/Mac/Lib/buildtools.py
@@ -74,7 +74,10 @@
 		progress = EasyDialogs.ProgressBar("Processing %s..."%os.path.split(filename)[1], 120)
 		progress.label("Compiling...")
 		progress.inc(0)
-	
+	# check for the script name being longer than 32 chars. This may trigger a bug
+	# on OSX that can destroy your sourcefile.
+	if '#' in os.path.split(filename)[1]:
+		raise BuildError, "BuildApplet could destroy your sourcefile on OSX, please rename: %s" % filename
 	# Read the source and compile it
 	# (there's no point overwriting the destination if it has a syntax error)