Do not apply the previous Windows backwards compatibility fix to old …

…versions (#663)

I tagged the previous build too soon and had not tried building Python 2.7 versions.  Looking
at the compiler versions used to build Python (https://wiki.python.org/moin/WindowsCompilers)
it looks like 3.5 and up need the new flags.

setup.py

@@ -167,8 +167,10 @@ def get_compiler_settings(version_str):
         # Unfortunately these are *hidden* settings.  I guess we should be glad they actually
         # made the settings.
         # https://lectem.github.io/msvc/reverse-engineering/build/2019/01/21/MSVC-hidden-flags.html
-        settings['extra_compile_args'].append('/d2FH4-')
-        settings['extra_link_args'].append('/d2:-FH4-')
+
+        if sys.hexversion >= 0x03050000:
+            settings['extra_compile_args'].append('/d2FH4-')
+            settings['extra_link_args'].append('/d2:-FH4-')
 
         settings['libraries'].append('odbc32')
         settings['libraries'].append('advapi32')