Revert r4644, "Updated NaCl's build system to use SCons 2.0.1."

src/native_client/site_scons/site_tools/target_platform_windows.py

Index: src/native_client/site_scons/site_tools/target_platform_windows.py
diff --git a/src/native_client/site_scons/site_tools/target_platform_windows.py b/src/native_client/site_scons/site_tools/target_platform_windows.py
index b8cead30509debe84caf215f5bd23ec726ea64c8..9633d62d3333e8904f73b3bffb6be4b4398902fe 100755
--- a/src/native_client/site_scons/site_tools/target_platform_windows.py
+++ b/src/native_client/site_scons/site_tools/target_platform_windows.py
@@ -261,11 +261,9 @@ def generate(env):
   # NOTE: SCons requires the use of this name, which fails gpylint.
   """SCons entry point for this tool."""
 
-  # TODO(ncbray): Several sections here are gated out on to prevent failure on
-  # non-windows platforms.  This appears to be SCons issue 1720 manifesting
-  # itself.  A more principled fix would be nice.
-
-  use_msvc_tools = env['PLATFORM'] in ('win32', 'cygwin')
+  # TODO: Several sections here are gated out on the mac to prevent failure.
+  # This appears to be SCons issue 1720 manifesting itself on Mac when using
+  # windows tools like msvs or msvc.
 
   # Preserve some variables that get blown away by the tools.
   saved = dict()
@@ -280,14 +278,14 @@ def generate(env):
     env.AppendENVPath('LIB', os.environ.get('LIB', '[]'))
 
   # Load various Visual Studio related tools.
-  if use_msvc_tools:
+  if env['PLATFORM'] != 'darwin':
     env.Tool('as')
     env.Tool('msvs')
     env.Tool('windows_hard_link')
 
   pre_msvc_env = env['ENV'].copy()
 
-  if use_msvc_tools:
+  if env['PLATFORM'] != 'darwin':
     env.Tool('msvc')
     env.Tool('mslib')
     env.Tool('mslink')
@@ -416,7 +414,7 @@ def generate(env):
   # TODO: mslink.py creates a shlibLinkAction which doesn't specify
   # '$SHLINKCOMSTR' as its command string.  This breaks --brief.  For now,
   # hack into the existing action and override its command string.
-  if use_msvc_tools:
+  if env['PLATFORM'] != 'darwin':
     env['SHLINKCOM'].list[0].cmdstr = '$SHLINKCOMSTR'
 
   # Restore saved flags.