* module/ice-9/boot-9.scm (current-language): New parameter.
* module/system/base/language.scm (*current-language*): Pull fluid from
parameter.
(current-language): Now a re-exported parameter.
* doc/ref/compiler.texi: Update reference from *current-language* fluid
to current-language parameter.
* module/system/base/compile.scm (compile-and-load):
* module/ice-9/top-repl.scm (top-repl): Default to the current language,
not to Scheme.
* module/ice-9/eval-string.scm:
* module/system/base/language.scm:
* module/system/repl/command.scm:
* module/system/repl/repl.scm: Update to use current-language parameter
and parameterize.
* module/Makefile.am:
* module/ice-9/eval-string.scm: New module, for use in implementing the
scm_c_eval_string_from_file_line suggestion.
* test-suite/Makefile.am:
* test-suite/tests/eval-string.test: New tests.
