It’s quite inelegant, but it leads to a more balanced profile:

--8<---------------cut here---------------start------------->8---
samples  %        symbol name
8079     23.3984  scm_string_eq
5649     16.3606  vm_debug_engine
5624     16.2882  scm_i_str2symbol
2840      8.2252  scm_ihashq
1755      5.0828  scm_i_string_hash
1637      4.7411  scm_fluid_ref
1027      2.9744  scm_i_string_ref
1011      2.9281  scm_hash_fn_get_handle
877       2.5400  scm_i_string_chars
793       2.2967  scm_module_variable
553       1.6016  scm_from_locale_stringn
471       1.3641  scm_from_stringn
426       1.2338  scm_sym2var
384       1.1121  scm_i_make_string
317       0.9181  scm_module_lookup
--8<---------------cut here---------------end--------------->8---

... and a 43% execution time improvement on a tight loop that does
‘string=’.

OK to commit?  Ideas for a better solution?

Thanks,
Ludo’.