-[NSFileManager fileSystemRepresentationWithPath:] not error safe - will crash on argument=nil

[Roland Schwingel]

Hi...

While migrating sources I found that fileSystemRepresentationWithPath: 
can not
correctly handle arguments equal to nil so it will crash on win. (I am 
using base-1.5.0)
This method is quite frequently used in NSFileManager on many locations.

- (const char*) fileSystemRepresentationWithPath: (NSString*)path
{
#ifdef __MINGW__
 /*
  * If path is in Unix format, transmogrify it so Windows functions
  * can handle it
  */  
 NSString    *newpath;
 const char    *c_path;
 int        l;

 path = [path stringByStandardizingPath];
 newpath = path;
 c_path = [path cString];
 l = strlen(c_path);

 if (c_path == 0)
   {
     return 0;
   }
...

If you supply nil for path it will crash in strlen() which is quite ugly.
I suggest to move
 l = strlen(c_path);

after the following if (c_path == 0) statement. So the method will 
correctly exit in this case.
(and bringing back OS4.2 behaviour).

What do you think? Is this change acceptable?

Roland