Building grep 2.9 on SunOS 4

[Michael Haardt]

Hello,

with a few tiny changes, grep builds on SunOS 4:

lib/hash.h and lib/version-etc.h should include <stddef.h> for
size_t.

In lib/errno.h, EILSEQ should be defined if the system does not do that.

lib/langinfo.in.h says:

/* A platform that lacks <langinfo.h>.  */

/* Assume that it also lacks <nl_types.h> and the nl_item type.  */

The assumption does not hold, SunOS 4 has langinfo.h, but lacks nl_types
and nl_item.

And finally, SunOS 4 lacks memmove (can use bcopy) and atexit.

Is there any chance to fix those things to make an old system happy?

Michael