Not an answer actually, but just a note to keep in mind.
As we could see, the problem of finding the location of running executable is quite tricky and platform-specific in Linux and Unix. One should think twice before doing that.
If you need your executable location for discovering some configuration or resource files, maybe you should follow the Unix way of placing files in the system: put configs to /etc or /usr/local/etc or in current user home directory, and /usr/share is a good place to put your resource files.
