Patch: switch to __builtin_alloca

[Tom Tromey]

>>>>> "Bryce" == Bryce McKinlay <bryce@albatross.co.nz> writes:

Bryce> Do you think we should remove all the "noconfigdirs="${libgcj}"
Bryce> stuff from the top-level configure.in? After all, the top-level
Bryce> won't try to build java unless "--enable-languages=java" is
Bryce> supplied anyway.

I want to convince Mark to enable Java automatically on supported
platforms.  Do we want to automatically build Java everywhere?  I
doubt we want to field a lot of "threads and gc don't work" bug
reports.  But maybe that is an exaggerated fear.

Tom