Add support for MIDL include directories

test/win/gyptest-midl-includedirs.py

Index: test/win/gyptest-midl-includedirs.py
diff --git a/test/win/gyptest-system-include.py b/test/win/gyptest-midl-includedirs.py
similarity index 63%
copy from test/win/gyptest-system-include.py
copy to test/win/gyptest-midl-includedirs.py
index 9a47d985383dd205eb843d2a460201a0b9da9979..05f637040937195dc7e1e843e05f9f5f9ee23a1b 100644
--- a/test/win/gyptest-system-include.py
+++ b/test/win/gyptest-midl-includedirs.py
@@ -5,7 +5,7 @@
 # found in the LICENSE file.
 
 """
-Checks that msvs_system_include_dirs works.
+Verify that 'midl_include_dirs' is handled.
 """
 
 import TestGyp
@@ -15,7 +15,7 @@ import sys
 if sys.platform == 'win32':
   test = TestGyp.TestGyp(formats=['msvs', 'ninja'])
 
-  CHDIR = 'system-include'
-  test.run_gyp('test.gyp', chdir=CHDIR)
-  test.build('test.gyp', test.ALL, chdir=CHDIR)
+  CHDIR = 'idl-includedirs'
+  test.run_gyp('idl-includedirs.gyp', chdir=CHDIR)
+  test.build('idl-includedirs.gyp', test.ALL, chdir=CHDIR)
   test.pass_test()