RFC: Only enable NIO2 by default when building with IcedTea

[Andrew Haley]

Andrew John Hughes wrote:
> It appears that some older versions of ecj fail when building the 
> NIO2 code:
> 
> 1. ERROR in ../../../src/share/classes/org/classpath/icedtea/java/nio/file/spi/AbstractPath.java (at line 276)
>    public final WatchKey register(WatchService watcher, WatchEvent.Kind<?>... events)
>         throws IOException
> 	                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> Name clash: The method register(WatchService, WatchEvent.Kind<?>...) of type AbstractPath has the same erasure as register(WatchService, WatchEvent.Kind<?>...) of type Watchable but does not override it
> ----------
> 
> It looks like this bug:
> 
> https://bugs.eclipse.org/bugs/show_bug.cgi?id=243820
> 
> The attached patch sets the NIO2 default based on whether with_icedtea is enabled.  So this works,
> and to be consistent with the rest of the autotools macro, it switches the values used from true/false
> to yes/no.
> 
> Okay to commit?

Would it not make more sense to:

1.  require a newer version of ecj in our build documentation

and

2.  tell people that if they have an old ecj they'll have to diable NIO2

?

Andrew.