Why do a great many targets disable libgcj by default in the toplevel 
configure.ac?

Where GCC provides a runtime library for a given language, I'd think the 
compiler isn't particularly useful without the library - and so if the 
compiler is built for that language, an attempt should be made to build 
the library, with a build failure if it isn't supported.  This is the 
situation with Go, for example - if you try to build with Go enabled for a 
target to which libgo hasn't yet been ported, you get a build failure in 
libgo telling you that the configuration you asked for isn't yet 
supported.

Thus, I'd think that the disabling of libgcj by default on many targets 
should be removed.  If it genuinely doesn't work on a given target, then 
the right setting is

    unsupported_languages="$unsupported_languages java"

though I'm not sure unsupported_languages works quite the right way (in my 
view, it should only disable inclusion of a language in 
--enable-languages=all; if you explicitly specify an unsupported language, 
it should still try to build it).  (And why (CC to maintainer) do some 
CRIS and MMIX targets list Fortran in unsupported languages?  I didn't 
think the Fortran libraries had any porting issues, unlike Java and Go and 
Ada.)

-- 
Joseph S. Myers
jos...@codesourcery.com

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