[RFC] Move --enable-languages logic to the toplevel

[Zack Weinberg]

> Zack Weinberg wrote:
>> I think it would be a good idea to disable Ada by default on the mainline,
>> so that people without an Ada bootstrap compiler handy are not unexpectedly
>> burnt by this problem.  Those who intend to build Ada can specify
>> --enable-languages=ada. 

Since there seems to be agreement on this issue, I have checked in the
appended patch on mainline.

zw

        * config-lang.in: Disable Ada by default until probe logic for
        a bootstrap Ada compiler can be moved to the top level configure
        script.

===================================================================
Index: ada/config-lang.in
--- ada/config-lang.in	10 Feb 2004 10:51:33 -0000	1.10
+++ ada/config-lang.in	13 Feb 2004 18:40:45 -0000
@@ -39,3 +39,9 @@ gtfiles="\$(srcdir)/ada/ada-tree.h \$(sr
 outputs=ada/Makefile
 
 target_libs="target-libada"
+
+# The logic for determining whether there is a bootstrap Ada compiler
+# available needs to be moved from gcc/configure to the toplevel configure,
+# so that target-libada is not built when there is no bootstrap Ada compiler.
+# Until then disable building this language by default.
+build_by_default=no