Crack down on redefinitions of built-ins.

* eval.c (builtin, eval_initing): New global variable.
(op_defun, op_defmacro): During initialization, record functions
and macros in builtin hash.
(builtin_reject_test): New static function.
(expand_macrolet): Perform builtin reject test for fbind, lbind,
and macrolet.
(regfun, reg_mac): Add symbol to builtin hash.
(eval_init): GC-protect new hash table variable and initialize it.
Set eval_initing to true over eval initialization.
The flip function is renamed fo flipargs.
(eval_compat_fixup): New function, for dealing with the
operator/function conflict over flip.

* eval.h (eval_compat_fixup): Declared.

* lib.c (compat_fixup): Call eval_compat_fixup.

* tests/011/macros-2.txr: This test was defining a macro called
while which is now illegal. Renamed to whilst.

* tests/011/macros-2.expected: Regenerated.

* txr.1:  Function flip renamed to flipargs and documented in
Compatibility section.

1 files changed, 1 insertions, 0 deletions

diff --git a/eval.h b/eval.h
index 39344c05..0f4b6fd7 100644
--- a/eval.h
+++ b/eval.h
@@ -54,3 +54,4 @@ val pprinl(val obj, val stream);
 val tprint(val obj, val out);
 
 void eval_init(void);
+void eval_compat_fixup(int compat_ver);