Merge from gnulib

Merge from gnulib

This incorporates:
2015-10-13 binary-io, u64, unistd: port to strict C
2015-09-26 c-ctype: do not worry about EBCDIC + char signed
2015-09-25 c-ctype: port better to z/OS EBCDIC
2015-09-25 gnulib-common.m4: fix gl_PROG_AR_RANLIB/AM_PROG_AR clash
* doc/misc/texinfo.tex, lib/binary-io.c, lib/c-ctype.h, lib/u64.c:
* lib/unistd.c, m4/gnulib-common.m4, m4/gnulib-comp.m4:
Copy from gnulib.