add run_with_env.cmd back in

This is part of https://github.com/ogrisel/python-appveyor-demo, and we
need it for pip to install native packages (like PyYAML). I shouldn't
have removed it.

appveyor.yml

@@ -1,6 +1,12 @@
 # Modified from https://github.com/ogrisel/python-appveyor-demo
 
 environment:
+  global:
+    # SDK v7.0 MSVC Express 2008's SetEnv.cmd script will fail if the
+    # /E:ON and /V:ON options are not enabled in the batch script intepreter
+    # See: http://stackoverflow.com/a/13751649/163740
+    CMD_IN_ENV: "cmd /E:ON /V:ON /C .\\appveyor\\run_with_env.cmd"
+
   matrix:
 
     # Pre-installed Python versions, which Appveyor may upgrade to

appveyor/run_with_env.cmd

@@ -0,0 +1,88 @@
+:: To build extensions for 64 bit Python 3, we need to configure environment
+:: variables to use the MSVC 2010 C++ compilers from GRMSDKX_EN_DVD.iso of:
+:: MS Windows SDK for Windows 7 and .NET Framework 4 (SDK v7.1)
+::
+:: To build extensions for 64 bit Python 2, we need to configure environment
+:: variables to use the MSVC 2008 C++ compilers from GRMSDKX_EN_DVD.iso of:
+:: MS Windows SDK for Windows 7 and .NET Framework 3.5 (SDK v7.0)
+::
+:: 32 bit builds, and 64-bit builds for 3.5 and beyond, do not require specific
+:: environment configurations.
+::
+:: Note: this script needs to be run with the /E:ON and /V:ON flags for the
+:: cmd interpreter, at least for (SDK v7.0)
+::
+:: More details at:
+:: https://github.com/cython/cython/wiki/64BitCythonExtensionsOnWindows
+:: http://stackoverflow.com/a/13751649/163740
+::
+:: Author: Olivier Grisel
+:: License: CC0 1.0 Universal: http://creativecommons.org/publicdomain/zero/1.0/
+::
+:: Notes about batch files for Python people:
+::
+:: Quotes in values are literally part of the values:
+::      SET FOO="bar"
+:: FOO is now five characters long: " b a r "
+:: If you don't want quotes, don't include them on the right-hand side.
+::
+:: The CALL lines at the end of this file look redundant, but if you move them
+:: outside of the IF clauses, they do not run properly in the SET_SDK_64==Y
+:: case, I don't know why.
+@ECHO OFF
+
+SET COMMAND_TO_RUN=%*
+SET WIN_SDK_ROOT=C:\Program Files\Microsoft SDKs\Windows
+SET WIN_WDK=c:\Program Files (x86)\Windows Kits\10\Include\wdf
+
+:: Extract the major and minor versions, and allow for the minor version to be
+:: more than 9.  This requires the version number to have two dots in it.
+SET MAJOR_PYTHON_VERSION=%PYTHON_VERSION:~0,1%
+IF "%PYTHON_VERSION:~3,1%" == "." (
+    SET MINOR_PYTHON_VERSION=%PYTHON_VERSION:~2,1%
+) ELSE (
+    SET MINOR_PYTHON_VERSION=%PYTHON_VERSION:~2,2%
+)
+
+:: Based on the Python version, determine what SDK version to use, and whether
+:: to set the SDK for 64-bit.
+IF %MAJOR_PYTHON_VERSION% == 2 (
+    SET WINDOWS_SDK_VERSION="v7.0"
+    SET SET_SDK_64=Y
+) ELSE (
+    IF %MAJOR_PYTHON_VERSION% == 3 (
+        SET WINDOWS_SDK_VERSION="v7.1"
+        IF %MINOR_PYTHON_VERSION% LEQ 4 (
+            SET SET_SDK_64=Y
+        ) ELSE (
+            SET SET_SDK_64=N
+            IF EXIST "%WIN_WDK%" (
+                :: See: https://connect.microsoft.com/VisualStudio/feedback/details/1610302/
+                REN "%WIN_WDK%" 0wdf
+            )
+        )
+    ) ELSE (
+        ECHO Unsupported Python version: "%MAJOR_PYTHON_VERSION%"
+        EXIT 1
+    )
+)
+
+IF %PYTHON_ARCH% == 64 (
+    IF %SET_SDK_64% == Y (
+        ECHO Configuring Windows SDK %WINDOWS_SDK_VERSION% for Python %MAJOR_PYTHON_VERSION% on a 64 bit architecture
+        SET DISTUTILS_USE_SDK=1
+        SET MSSdk=1
+        "%WIN_SDK_ROOT%\%WINDOWS_SDK_VERSION%\Setup\WindowsSdkVer.exe" -q -version:%WINDOWS_SDK_VERSION%
+        "%WIN_SDK_ROOT%\%WINDOWS_SDK_VERSION%\Bin\SetEnv.cmd" /x64 /release
+        ECHO Executing: %COMMAND_TO_RUN%
+        call %COMMAND_TO_RUN% || EXIT 1
+    ) ELSE (
+        ECHO Using default MSVC build environment for 64 bit architecture
+        ECHO Executing: %COMMAND_TO_RUN%
+        call %COMMAND_TO_RUN% || EXIT 1
+    )
+) ELSE (
+    ECHO Using default MSVC build environment for 32 bit architecture
+    ECHO Executing: %COMMAND_TO_RUN%
+    call %COMMAND_TO_RUN% || EXIT 1
+)