Throughout, make these changes
Copyright headers: GNU Mes
First mention of name: GNU Mes
Website: https://www.gnu.org/software/mes
Git: git://git.savannah.gnu.org/mes.git
* include/sys/types.h [__PTRDIFF_T]: Extra guard for ptrdiff_t.
[__SIZE_T]: Extra guard for size_t.
* include/stdlib.h: Include alloca; remove alloca prototype,
* include/errno.h: Add E2BIG.