Clean up functions creating Lisp strings from C strings
We have the following functions for that:
ecl_make_simple_base_string
ecl_make_constant_base_string
make_base_string_copy
According to our documentation, ecl_make_simple_base_string
is suppossed to copy the string argument, but it doesn't actually do that, instead it is completely equivalent to ecl_make_constant_base_string
. make_base_string_copy
does copy its argument, but it has no length parameter and the function name is not prefixed with ecl_
and thus belongs in legacy.h.