This is to be used with the autoPatchelf command and allows to only
patch a specific file or directory without recursing into
subdirectories.
Apart from being able to run the command in a standalone way, as
detailled in the previous commit this is also needed for the Android SDK
emulator, because according to @svanderburg there are subdirectories we
don't want to patch.
The reason why I didn't use GNU getopt is that it might not be available
on all operating systems and the getopts bash builtin doesn't support
long arguments. Apart from that, the implementation for recognizing the
flag is pretty trivial and it's also using bash builtins only, so if we
want to do something really fancy someday, we can still change it.
Signed-off-by: aszlig <aszlig@nix.build>