Update from gnulib

Update from gnulib

This incorporates:
2016-09-15 stdint: support new _WIDTH macros
2016-09-15 limits-h: new module
2016-09-15 sys_types: avoid glibc 2.25 warnings about major()
2016-09-15 extensions: port to more ISO C TSes
2016-09-13 intprops: new macro TYPE_WIDTH
2016-09-13 extensions: port to recent ISO C TRs
* .gitignore: Add lib/limits.h.
* doc/misc/texinfo.tex, lib/ftoastr.h, lib/intprops.h:
* lib/stdint.in.h, m4/extensions.m4, m4/stdint.m4, m4/stdio_h.m4:
* m4/sys_types_h.m4: Copy from gnulib.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* lib/limits.in.h, m4/limits-h.m4: New files, copie from gnulib.
* nt/gnulib.mk: Merge changes from lib/gnulib.mk.