win msvs: make express editions not use x64-x64 compiler

VS2012 express and others do not include a 64 bit compiler
that generates 64 bit code. This patch makes it so the
64 bit compiler is only enabled when not using a Visual
Studio express edition.

Patch from david@sankelsoftware.com.

R=scottmg@chromium.org

Review URL: https://codereview.chromium.org/101223013

git-svn-id: http://gyp.googlecode.com/svn/trunk@1829 78cadc50-ecff-11dd-a971-7dbc132099af

AUTHORS

@@ -7,4 +7,5 @@ Yandex LLC
 
 Steven Knight <knight@baldmt.com>
 Ryan Norton <rnorton10@gmail.com>
+David J. Sankel <david@sankelsoftware.com>
 Eric N. Vander Weele <ericvw@gmail.com>

pylib/gyp/MSVSVersion.py

@@ -96,9 +96,11 @@ def SetupScript(self, target_arch):
       else:
         assert target_arch == 'x64'
         arg = 'x86_amd64'
-        if (os.environ.get('PROCESSOR_ARCHITECTURE') == 'AMD64' or
+        # Use the 64-on-64 compiler if we're not using an express
+        # edition and we're running on a 64bit OS.
+        if self.short_name[-1] != 'e' and (
+            os.environ.get('PROCESSOR_ARCHITECTURE') == 'AMD64' or
             os.environ.get('PROCESSOR_ARCHITEW6432') == 'AMD64'):
-          # Use the 64-on-64 compiler if we can.
           arg = 'amd64'
         return [os.path.normpath(
             os.path.join(self.path, 'VC/vcvarsall.bat')), arg]