[PATCH] Bug 3229: cf_gen.cc dependency removal / conversion to C++

 This converts the bulk of cf_gen to C++ OOP code.

  * char* tree members to std::string. Which eliminates xstrdup() and
 xis*() calls.

  * structs to classes and replaces calloc/free with new/delete.

  * link cf_gen_depends.cci directly to autoconf.h defines.

 The result of these is that we can erase the dependencies on util.h,
 time.cc, config.h, libcompat.la and libmisc.la. Directly fixing bug 3229
 and other related cross-compile issues that keep appearing on various
 OS.

 I'm not sure if we can also drop dependencies on XTRA_LIBS and
 MING_LIBS. that would be nice. I've left them for now.

 There is a bit further cleanup we can do. Replacing several classes
 with std::list<std::string>.

 The final remaining cross-compiler bug is to generate cf_gen for the
 local build machine rather than the destination host environment.

 Amos