Add support for large files. Merge glibc 2.1.2.

Add support for large files.  Merge glibc 2.1.2.

* b2m.c, emacsclient.c, emacsserver.c, fakemail.c, make-docfile.c,
movemail.c, pop.c:
Do not include <stdlib.h>, as <config.h> does this now.

* b2m.c, emacsserver.c, etags.c, profile.c:
Include <config.h> before any system include files.

* emacsclient.c, emacsserver.c, fakemail.c, movemail.c, pop.c,
test-distrib.c:
(read, write, open, close): Do not undef.

* getopt.c, getopt1.c: Adopt glibc 2.1.2, with the following fix:
(const): Do not define if HAVE_CONFIG_H; that's config.h's job.

* getopt.h: Adopt glibc 2.1.2.