Re: Guile BUG: What's wrong with this?

[Bruce Korb]

scm_from_locale_stringn() makes an optimization when the length is zero.
It returns an immutable string of length zero.  For reasons I no longer
remember, I had my own ag_scm_string_upcase that called
scm_string_upcase_x, presuming that scm_from_locale_stringn had returned
a writable string.

Two possible fixes:

1. remove the "optimization"
2. check the length in scm_string_upcase_x before choking.

The reason for the seg fault is that scm_backtrace() faulted.
I called it in the on_exit path and it couldn't cope.