core+mini-mes: Replace manual snippets by snarfed includes.
* build-aux/mes-snarf.scm (symbol->source, function->header,
function->source, function->environment): Add workarounds to
avoid struct-copy initializers.
* GNUmakefile (mini-mes): Snarf symbols and functions.
* scaffold/mini-mes.c: Include mini-mes.h, mini-mes.symbols.h,
mini-mes.symbols.i, mini-mes.i, mini-mes.environment.i.
Add snarfable symbol/special definitions.
(type_t): Prefix all types with `T', update users.
(assert_defined, gc_push_frame, gc_peek_frame, gc_init_cells): Mark
as internal.
* mes.c (type_t): Prefix all types with `T', update users.
* scaffold/mini-mes.c (eq_p, type_, car_, cdr_,
list_of_char_equal_p, lookup_macro, write_byte): New functions (from
mes.c).
(assq): Add debugging, workaround.