Finish porting hammer's library to windows

We port registry by importing the (public domain) openbsd implementation
of the tfind/tsearch POSIX binary tree search functions.

These are only necessary when building on non-posix platforms

tools/windows/hammer_lib_src_list

@@ -9,7 +9,9 @@ desugar.c
 glue.c 
 hammer.c 
 pprint.c
+registry.c
 system_allocator.c
+tsearch.c
 parsers/action.c 
 parsers/and.c 
 parsers/attr_bool.c