Disable xlib peers by default, add --enable-java-awt configure option

[Tom Tromey]

Bryce> Heres a patch to do that. The idea is that you can specify a
Bryce> comma separated list of peers to build in the --enable-java-awt
Bryce> argument

Cool.

Bryce> It works nicely but I'd also like to have it complain
Bryce> appropriatly if someone specifies "--enable-java-awt=xlib" but
Bryce> doesn't have X headers installed or whatever. It seems that the
Bryce> test for "if [test "$no_x" = yes]" doesn't actually work, even
Bryce> though it definatly did seem work inside an AM_CONDITIONAL
Bryce> previously ("--without-x" stopped libgcjx being build).

Bryce> Any ideas on that one Tom?

The code in question needs to come after AC_PATH_XTRA.

Tom