Add a prototype implementation of stdio-like routines for accessing the VFS.
This is intended as documentation.  The code is untested. There is no
guarantee that any of this will ever make it into trunk.  Substantial
revision is possible prior to reaching trunk, if it ever does.

FossilOrigin-Name: 8936542b225836f5f4a789e1ecc1451f6a1e120d
4 files changed