Drop support for Windows 2000; allow any XP API (but not Vista+).
Drop SDK version configuration for Tk compilation, to not bind it to W2k
anymore. Binding it to XP would conflict with Tk's own binding of tkMenu to W2k.
diff --git a/PCbuild/build_tkinter.py b/PCbuild/build_tkinter.py
index 4196cf3..9f08631 100644
--- a/PCbuild/build_tkinter.py
+++ b/PCbuild/build_tkinter.py
@@ -16,11 +16,7 @@
 TIX = "tix-8.4.3.x"
 
 ROOT = os.path.abspath(os.path.join(here, par, par))
-# Windows 2000 compatibility: WINVER 0x0500
-# http://msdn2.microsoft.com/en-us/library/aa383745.aspx
-NMAKE = ('nmake /nologo /f %s '
-    'COMPILERFLAGS=\"-DWINVER=0x0500 -D_WIN32_WINNT=0x0500 -DNTDDI_VERSION=NTDDI_WIN2KSP4\" '
-    '%s %s')
+NMAKE = ('nmake /nologo /f %s %s %s')
 
 def nmake(makefile, command="", **kw):
     defines = ' '.join(k+'='+str(v) for k, v in kw.items())