scm_debug_opts to debug.c, backtrace on by default, scm_*_opts internal linkage

* libguile/eval.c:
* libguile/debug.c (scm_debug_opts): Move here, from eval.c. Change
  SCM_BACKTRACE_P to 1, initially.

* libguile/private-options.h: Make all options vars private.

libguile/debug.c

@@ -59,6 +59,39 @@
 
 
 
+/*
+ * Debugging options.
+ */
+
+scm_t_option scm_debug_opts[] = {
+  { SCM_OPTION_BOOLEAN, "backwards", 0,
+    "Display backtrace in anti-chronological order." },
+  { SCM_OPTION_INTEGER, "width", 79, "Maximal width of backtrace." },
+  { SCM_OPTION_INTEGER, "depth", 20, "Maximal length of printed backtrace." },
+  { SCM_OPTION_BOOLEAN, "backtrace", 1, "Show backtrace on error." },
+  /* This default stack limit will be overridden by init_stack_limit(),
+     if we have getrlimit() and the stack limit is not INFINITY. But it is still
+     important, as some systems have both the soft and the hard limits set to
+     INFINITY; in that case we fall back to this value.
+
+     The situation is aggravated by certain compilers, which can consume
+     "beaucoup de stack", as they say in France.
+
+     See http://thread.gmane.org/gmane.lisp.guile.devel/8599/focus=8662 for
+     more discussion. This setting is 640 KB on 32-bit arches (should be enough
+     for anyone!) or a whoppin' 1280 KB on 64-bit arches.
+  */
+  { SCM_OPTION_INTEGER, "stack", 160000, "Stack size limit (measured in words; 0 = no check)." },
+  { SCM_OPTION_SCM, "show-file-name", (unsigned long)SCM_BOOL_T,
+    "Show file names and line numbers "
+    "in backtraces when not `#f'.  A value of `base' "
+    "displays only base names, while `#t' displays full names."},
+  { SCM_OPTION_BOOLEAN, "warn-deprecated", 0,
+    "Warn when deprecated features are used." },
+  { 0 }, 
+};
+
+
 /* {Run time control of the debugging evaluator}
  */