Free a hashed string
void SLang_free_slstring (char *s)
The SLang_free_slstring function is used to free a hashed
string such as one returned by SLang_create_slstring,
SLang_create_nslstring, or SLang_create_static_slstring.
If s is NULL, the routine does nothing.
SLang_create_slstring, SLang_create_nslstring, SLang_create_static_slstring