Merge from gnulib
This incorporates:
2015-04-24 file-has-acl: new module, split from acl
2015-04-24 manywarnings: add GCC 5.1 warnings
2015-04-21 lstat: fix cross-compilation 'ln -s' problem
2015-04-15 qacl: Simplify HP-UX acl_nontrivial check
2015-04-15 acl: On Linux, check for acls without libacl
2015-04-14 tempname: avoid unused parameter warnings (trivial)
* lib/acl-internal.c: New file, from gnulib.
* lib/file-has-acl.c: Remove; no longer imported from gnulib.
* lib/acl-internal.h, lib/gnulib.mk, lib/qcopy-acl.c, lib/tempname.c:
* m4/acl.m4, m4/gnulib-comp.m4, m4/lstat.m4, m4/manywarnings.m4:
Update from gnulib.