* module/mes/as-i386.mes (i386:accu-or-base): New function.
* module/mes/as-i386.scm: Export it.
* module/language/c99/compiler.mes (expr->accu): Use it; support bitwise or.
* scaffold/t.c (math_test): Test it.
* scaffold/mini-mes.c (logior): Use it.