There are a couple of errors when trying to build the gtkd library on windows. These are a result of assuming Tango/gtkd development is being done on linux only.
(1) Fix gtkc/paths.d for tango
Tango does not include the registry class that Phobos has, so gtkd does not compile here. A simple workaround is to assign a default path link for gtk+ dll directory and version out the registry portion. An alternate solution is port std.windows.registry from Phobos to Tango (a fair bit of work). A third option is to access the c registry functions from windows directly (still a fair bit of work).
(2) Fix the wrapper for glib/Spawn.d
Currently Spawn.d imports tango.stdc.posix.stdio which is linux only. This causes invalid definition errors during compile. The linux specific symbols are used in function execAsyncWithPipes in the same file with Tango. Apparently Phobos provides the symbols for win32 in std.c.stdio whereas Tango only provides them in tango.stdc.posix.stdio (linux only). This may be an issue with gtkd or Tango. Either way it needs to be fixed, perhaps reporting the problem to the Tango Team.
I worked around both these solutions with some version statements and was able to compile the cairo and gtkD examples using Tango. But we need more permanent fixes for these.