GitLab

This incorporates:
2016-12-14 xalloc-oversized: check for PTRDIFF_MAX too
2016-12-12 fpending: port to native Windows with MSVC
* .gitignore: Do not ignore lib/stdio-impl.h.
* lib/fpending.c, lib/xalloc-oversized.h, m4/fpending.m4:
Copy from gnulib.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* lib/stdio-impl.h:
New file, copied from gnulib.
* nt/gnulib.mk (EXTRA_DIST): Add stdio-impl.h.