* module/mes/libc-i386.mes (i386:va-arg): New function.
* module/mes/libc-i386.scm (mes): Export it.
* module/mes/libc.mes (printf): New function.
(libc): Add it.
* libc/include/stdio.h: New file.
* module/language/c99/compiler.mes (c99-input->ast): Add libc/include
to include path.
(ast-info): Handle (skip) ellipsis in function declaration.