mescc: Be silent.

mescc: Be silent.

* module/mescc/M1.scm (infos->M1, info->M1): Add verbose?.  Move
debugging into verbose? > 1.
* module/mescc/compile.scm (c99-input->info, c99-ast->info): Likewise.
(mescc:trace-verbose): Rename from mescc:trace.
(mescc:trace): New function.
* module/mescc.scm (mescc:main): Likewise.
* module/mescc/mescc.scm (mescc:preprocess, c->ast mescc:compile,
c->info, E->info): Likewise.
* module/mescc/preprocess.scm (c99-input->full-ast, c99-input->ast):
Likewise.