The 'gcc/configure' script sources all 'gcc/*/config-lang.in' files, but fails
to emit such dependency information into the build machinery. That means,
currently, when something gets changed in a 'gcc/*/config-lang.in' file, this
is not noticed, and doesn't propagate through the build machinery.
Handling of configure fragments is modelled in the same way as it already
exists for Makefile fragments.
gcc/
* Makefile.in (LANG_CONFIGUREFRAGS): Define.
(config.status): Use/depend on it.
* configure.ac (all_lang_configurefrags): Track, 'AC_SUBST'.
* configure: Regenerate.
From-SVN: r278035
