This incorporates:
2016-04-03 stdint: detect good enough pre-C++11 stdint.h in C++ mode
2016-04-01 stddef: support configuring with g++
* doc/misc/texinfo.tex, lib/stddef.in.h, m4/stdint.m4:
Copy from gnulib.
2014-12-12 stddef: support C11's max_align_t
2014-12-08 apply _GL_ATTRIBUTE_PURE to some inline functions
2014-12-02 support GNU format printf and scanf on mingw
* doc/misc/texinfo.tex, lib/stat-time.h, lib/stddef.in.h:
* lib/timespec.h, m4/extensions.m4, m4/stddef_h.m4, m4/stdio_h.m4:
Update from gnulib.
* lib/gnulib.mk: Regenerate.
