Backport change from 1.2.0: doc/Makefile.am: Write generated man page to a temporary file, then atomically rename, to avoid leaving an empty or partial man page behind if docbook-to-man dies (I managed to ship an empty cad3d.1 in 1.1.16).
git-svn-id: file:///home/survex-svn/survex/branches/1.0@3697 4b37db11-9a0c-4f06-9ece-9ab7cdaee568
