MSVC: disable warning about constant conditional expressions

The standard headers for Visual Studio 2008 generate a warning about
constant conditional expressions when compiled with exception support
disabled.  This is caused by the _CATCH_ALL macro in xstddef which is
defined thusly:

  #ifdef _HAS_EXCEPTIONS
  #define _CATCH_ALL } catch (...) {
  #else
  #define _CATCH_ALL } if (0) {
  #endif

diff --git a/configure.py b/configure.py
index 1c97db7..92d0573 100755 (executable)
--- a/configure.py
+++ b/configure.py
@@ -302,6 +302,8 @@ if platform.is_msvc():
               '/WX',  # Warnings as errors.
               '/wd4530', '/wd4100', '/wd4706',
               '/wd4512', '/wd4800', '/wd4702', '/wd4819',
+              # Disable warnings about constant conditional expressions.
+              '/wd4127',
               # Disable warnings about passing "this" during initialization.
               '/wd4355',
               # Disable warnings about ignored typedef in DbgHelp.h