configure: implement full-repl option.

This patch unbundles the building of the full-featured REPL
from HAVE_TERMIOS. We make it subject to its own configuration
option CONFIG_FULL_REPL, which is 1 by default. This way, the
downstream users or package maintainers can build TXR without
the full-featured REPL even if HAVE_TERMIOS is 1, and the
other termios material is built-in.

* configure (full_repl): New variable.
(help): Include full-repl in the help text.
In the termios test, if we don't detect termios, then
negate the full_repl variable.
In the final config variable generation section, generate
the  CONFIG_FULL_REPL 1 define in config.h, if full_repl
is true, ensuring it is subject to HAVE_TERMIOS, too.

* linenoise/linenoise.c: Replace HAVE_TERMIOS with
CONFIG_FULL_REPL.

* linenoise/linenoise.h: Likewise.

* parser.c: Likewise.

* txr.c: Likewise and ...
(if_termios): Macro renamed to if_full_repl.
(if_full_repl): New macro.
(opt_noninteractive): Use if_full_repl macro for
initializing.
(banner): Use if_ful_repl macro instead of if_termios.

1 files changed, 1 insertions, 1 deletions

diff --git a/linenoise/linenoise.h b/linenoise/linenoise.h
index 4ad3ce64..5564afb4 100644
--- a/linenoise/linenoise.h
+++ b/linenoise/linenoise.h
@@ -92,7 +92,7 @@ typedef struct lino_os {
   wide_disp                                                             \
 }
 
-#if HAVE_TERMIOS
+#if CONFIG_FULL_REPL
 
 typedef struct lino_completions {
     size_t len;