Bug 910487 - Hack binary Python extensions into building on Windows; r=mshal

build/virtualenv/populate_virtualenv.py

@@ -12,6 +12,7 @@ import os
 import shutil
 import subprocess
 import sys
+import warnings
 
 
 # Minimum version of Python required to build.
@@ -273,6 +274,33 @@ class VirtualenvManager(object):
                 old_env_variables[k] = os.environ[k]
                 del os.environ[k]
 
+            # HACK ALERT.
+            #
+            # The following adjustment to the VSNNCOMNTOOLS environment
+            # variables are wrong. This is done as a hack to facilitate the
+            # building of binary Python packages - notably psutil - on Windows
+            # machines that don't have the Visual Studio 2008 binaries
+            # installed. This hack assumes the Python on that system was built
+            # with Visual Studio 2008. The hack is wrong for the reasons
+            # explained at
+            # http://stackoverflow.com/questions/3047542/building-lxml-for-python-2-7-on-windows/5122521#5122521.
+            if sys.platform in ('win32', 'cygwin') and \
+                'VS90COMNTOOLS' not in os.environ:
+
+                warnings.warn('Hacking environment to allow binary Python '
+                    'extensions to build. You can make this warning go away '
+                    'by installing Visual Studio 2008. You can download the '
+                    'Express Edition installer from '
+                    'http://go.microsoft.com/?linkid=7729279')
+
+                # We list in order from oldest to newest to prefer the closest
+                # to 2008 so differences are minimized.
+                for ver in ('100', '110', '120'):
+                    var = 'VS%sCOMNTOOLS' % ver
+                    if var in os.environ:
+                        os.environ['VS90COMNTOOLS'] = os.environ[var]
+                        break
+
             for package in packages:
                 handle_package(package)
         finally: