diff --git a/pyconfig.h b/pyconfig.h
index 35a6bf1e..cd90e7d7 100644
--- a/pyconfig.h
+++ b/pyconfig.h
@@ -19,7 +19,7 @@
 #  define PY_INLINE_FRIEND ::py
 # endif
 
-# if !defined(__GNUC__) && !defined(__MWERKS__) && !defined(__BORLANDC__) && defined(_MSC_VER)
+# if defined(BOOST_MSVC)
 #  define PY_COMPILER_IS_MSVC 1
 #  if _MSC_VER <= 1200
 #   define PY_MSVC6_OR_EARLIER 1
@@ -29,6 +29,17 @@
 
 # endif
 
+// Work around the broken library implementation/strict ansi checking on some
+// EDG-based compilers (e.g. alpha), which incorrectly warn that the result of
+// offsetof() is not an integer constant expression.
+# if defined(__DECCXX_VER) && __DECCXX_VER <= 60290024
+#  define PY_OFFSETOF(s_name, s_member) \
+        ((size_t)__INTADDR__(&(((s_name *)0)->s_member)))
+# else
+#  define PY_OFFSETOF(s_name, s_member) \
+        offsetof(s_name, s_member)
+# endif
+
 // The STLport puts all of the standard 'C' library names in std (as far as the
 // user is concerned), but without it you need a fix if you're using MSVC.
 # if defined(PY_MSVC6_OR_EARLIER) && !defined(__STLPORT)