Attached are the stddef* files.
Some things to note:
1) ./gnulib/lib/stddef.h exists at checkout
2) after "autogen.sh" and "configure", ./gnulib/lib/stddef.h continues to exist with "make". But "make distclean" will wipe out ./gnulib/lib/stddef.h
3) after "autogen.sh" and "configure", "make -C gnulib/lib stddef.h"
make: Entering directory '/home/user/Desktop/texinfo/gnulib/lib'
rm -f stddef.h
make: Leaving directory '/home/user/Desktop/texinfo/gnulib/lib'
4) $ printenv | grep GNU
GNULIB_SRCDIR=/home/user/Desktop/gnulib/
GNULIB_TOOL=/home/user/Desktop/gnulib/gnulib-tool
Gavin, if you would like to remote in, you may. I am just running in a temporary virtualbox snapshot.