- Issue #16754: Fix the incorrect shared library extension on linux. Introduce
  two makefile macros SHLIB_SUFFIX and EXT_SUFFIX. SO now has the value of
  SHLIB_SUFFIX again (as in 2.x and 3.1). The SO macro is removed in 3.4.
diff --git a/Lib/sysconfig.py b/Lib/sysconfig.py
index 253e2ef..5b3a994 100644
--- a/Lib/sysconfig.py
+++ b/Lib/sysconfig.py
@@ -360,6 +360,7 @@
     vars['BINLIBDEST'] = get_path('platstdlib')
     vars['INCLUDEPY'] = get_path('include')
     vars['SO'] = '.pyd'
+    vars['EXT_SUFFIX'] = '.pyd'
     vars['EXE'] = '.exe'
     vars['VERSION'] = _PY_VERSION_SHORT_NO_DOT
     vars['BINDIR'] = os.path.dirname(_safe_realpath(sys.executable))