refs #388
Create a sub-directory 'lib/yat' in which files from yat are
placed. The files may be updated via 'make fetch', see file README for
more details on how to change which files are updated/copied through
this mechanism.
The reason we do not use subversion's external mechanism is that we
don't want the files to be synchronised with yat automatically. We
want the update to be moderated by some developer.
I chose to fetch files using the svn client rather than wget because
the svn allows us to get an Id string with information from the yat
repository. 'wget' would just download the file as it appears on the
server that is the string is not expanded.
The file 'config_public.h' is created by configure just as in
yat. This implies that automake adds $(top_builddir)/lib/yat to the
include path so unless in a VPATH build $(top_srcdir)/lib/yat is in
the include path. As we have already added $(top_srcdir)/lib to the
include path, and there are both a lib/utility.h and a
lib/yat/utility.h it is not obvious which file is included when having
'include "utility.h"'. For this reason, when being in bin/ and test/
it is needed to include "../lib/utility.h" rather than "utility.h"
when we want to include 'lib/utility.h'.
