Use unmodified WAF check_python_headers on Windows

Unsure why this was needed in the first place as it seems to build fine now.
Presumably lots of things have been fixed in WAF since this was a problem.

wscript

@@ -91,13 +91,7 @@ def configure(conf):
         conf.env.PYTHON = conf.options.python
     conf.load('python')
     conf.check_python_version(minver=(3,7,0))
-    if isWindows:
-        # Search for the Python headers without doing some stuff that could
-        # incorrectly fail on Windows. See my_check_python_headers below.
-        # TODO: Check if it can/should be used on other platforms too.
-        conf.my_check_python_headers()
-    else:
-        conf.check_python_headers(features='pyext')
+    conf.check_python_headers(features='pyext')
 
     # fetch and save the debug options
     conf.env.debug = conf.options.debug