Merge from gnulib

Merge from gnulib

This incorporates:
2015-05-27 qacl: Reimplement qset_acl and qcopy_acl (Bug#20666)
2015-05-27 file-has-acl: Split feature tests again (Bug#20667)
2015-05-27 string: fix build failure on BSD/OSX with FORTIFY_SOURCE
2015-05-26 stdio: limit __gnu_printf__ witness to gcc 4.4+
2015-05-26 inttypes: force correct mingw PRIdMAX even without <stdio.h>
2015-05-26 stdio: fix probe on mingw under gcc 5.1
* admin/merge-gnulib (GNULIB_MODULES):
Replace qacl with qcopy-acl, since we don't need the rest of qacl.
* doc/misc/texinfo.tex, lib/acl-internal.c, lib/acl-internal.h:
* lib/inttypes.in.h, lib/qcopy-acl.c, lib/qset-acl.c:
* lib/string.in.h, m4/acl.m4, m4/stdio_h.m4:
Get latest versions from gnulib.
* lib/get-permissions.c, lib/set-permissions.c: New files.
* lib/gnulib.mk, m4/gnulib-comp.m4:
Regenerate.
* nt/gnulib.mk: Merge lib/gnulib.mk changes by hand.