tests: suppress warnings in seq.tl.

When tests/012/compile.tl compiles tests/012/seq.tl, there
are now some compiler warnings due to constant expressions
that throw. We introduce a new compiler option to suppress
them, and then use it.

* stdlib/comp-opts.tl: New file. The definitions related
to compiler options are moved here out of compile.tl,
so that optimize.tl can use them.

* stdlib/compiler.tl (compile-opts, %warning-syms%,
when-opt, *compile-opts*, opt-controlled-diag): Moved to
comp-opts.tl. New constant-throws option added to
compile-opts and %warning-syms%.
(safe-constantp): Make the constant expression throws
diagnostic conditional on the new option.

* stdlib/optimize.tl: Load comp-opts file.
(basic-blocks do-peephole-block): Make diagnostic
about throwing situation subject to constant-throws
option.

* tests/012/seq.tl: Turn off constant-throws warning
option before the ref tests that work with ranges.
Fix: one of the expressions calls refs with the
wrong number of arguments, which was unintentional.

* txr.1: Document new diagnostic option.

1 files changed, 3 insertions, 1 deletions

diff --git a/tests/012/seq.tl b/tests/012/seq.tl
index c48296bd..262c7739 100644
--- a/tests/012/seq.tl
+++ b/tests/012/seq.tl
@@ -826,9 +826,11 @@
   [apply mapcar join (list-seq "aaa".."zzz")]
   (transpose (list-seq "aaa".."zzz")))
 
+(eval-only (set *compile-opts*.constant-throws nil))
+
 (mtest
   (ref "a".."z" 0) :error
-  (ref (rcons 'foo 'bar)) :error)
+  (ref (rcons 'foo 'bar) 0) :error)
 
 (mtest
   (ref 1..6 0) 1