non-standard functions

[Peter]

Current yat uses some posix functions like opendir, fnmatch, and basename, which are not included in any C or C++ standard. Not a big deal but I think we should either

1. Document the requirement
2. or have configure check if functions are available, and if not exclude related functionality from compilation of libyat.
3. or similar to 2. but provide workaround code

For 2. it's perhaps a good idea to PP guard out functions from header files as well, but it's a bit dirty to expose too much of config.h content in the public headers. For 3. I have no idea how difficult things are to implement, but I guess in that case it's better to take the big leap and pull in gnulib since this is exactly what they are doing. While typing I realize there is an option 1 1/2 too: Document the requirements and check for them in configure (prefer configure error over compilation error).

[Peter]

see comment for ticket #854