gnustep-gui and blocks support

[Luboš Doležel]

Hi,

I was playing around with NSSavePanel and noticed gnustep-gui doesn't 
support methods such as

- (void)beginSheetModalForWindow:(NSWindow *)window 
completionHandler:(void (^)(NSInteger result))handler

I also couldn't find any other method that would use blocks. Since there 
already is blocks support in libobjc2, it's a shame.

Now I understand that blocks support is something that needs to be 
detected and enabled by configure, so that runtimes/compilers without 
blocks still work.

Well, I don't feel up to the task of doing the detection, but would like 
to contribute methods like the one above. Could someone else please 
introduce the required changes? :-)

--
Luboš Doležel