sort: prudently make it subject to compat value

* eval.c (eval_init): If opt_compat is 237 or less, make sort
and shuffle destructive.

* share/txr/stdlib/getopts.tl (opthelp): Revert previous
change, restoring use of copy-list and use nsort instead of
sort, so the function is not affected by the 237 compatibility
being turned on.

* txr.1: Add compatibility notes.

1 files changed, 4 insertions, 2 deletions

diff --git a/eval.c b/eval.c
index 4d0cc137..2d547d44 100644
--- a/eval.c
+++ b/eval.c
@@ -6893,9 +6893,11 @@ void eval_init(void)
   reg_fun(intern(lit("improper-plist-to-alist"), user_package), func_n2(improper_plist_to_alist));
   reg_fun(intern(lit("merge"), user_package), func_n4o(merge_wrap, 2));
   reg_fun(intern(lit("nsort"), user_package), func_n3o(nsort, 1));
-  reg_fun(intern(lit("sort"), user_package), func_n3o(sort, 1));
+  reg_fun(intern(lit("sort"), user_package),
+          func_n3o(if3(opt_compat && opt_compat <= 237, nsort, sort), 1));
   reg_fun(intern(lit("nshuffle"), user_package), func_n1(nshuffle));
-  reg_fun(intern(lit("shuffle"), user_package), func_n1(shuffle));
+  reg_fun(intern(lit("shuffle"), user_package),
+          func_n1(if3(opt_compat && opt_compat <= 237, nshuffle, shuffle)));
   reg_fun(intern(lit("find"), user_package), func_n4o(find, 2));
   reg_fun(intern(lit("rfind"), user_package), func_n4o(rfind, 2));
   reg_fun(intern(lit("find-if"), user_package), func_n3o(find_if, 2));