This incorporates:
2018-01-01 maint: Run 'make update-copyright'
2017-12-29 Add cross-compilation results for GNU/Hurd.
2017-12-12 explicit_bzero: port to macOS + Clang 9.0.0
This incorporates:
2016-12-19 stdint: Fix WINT_MAX to match wint_t on mingw
2016-12-18 getopt: Fix link error for users of getopt() in <unistd.h>
2016-12-17 getlogin: Port to newer mingw
2016-12-17 stdint: Fix WINT_MAX to match wint_t on MSVC
2016-12-17 Avoid redefinition errors on MSVC
* lib/getopt.in.h, lib/stdint.in.h, lib/stdio.in.h, lib/unistd.in.h:
* m4/stdint.m4, m4/unistd_h.m4:
Copy from gnulib.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
Plus, this commit updates the indenting on copyright notices to
match that of gnulib.
