RFC: Only enable NIO2 by default when building with IcedTea

[Matthias Klose]

Andrew Haley schrieb:
> 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

documenting the requirement sounds fine.

For distributing ecj I am interested in one version which can be used to build
ecj1 and a vanilla ecj which is used as standalone compiler, or javac for
java-gcj-compat. Last time I checked an update to the next ecj-3.3.x release
didn't work well for libgcj. I'll try to check the ecj-3.4.2 release and see
how/if this works when used as ecj1. Are there any patches available for
ecj-3.4.2 to build it as ecj1?

  Matthias