Compile _decimal without asserts and update benchmark results.
diff --git a/Doc/whatsnew/3.3.rst b/Doc/whatsnew/3.3.rst
index e019ea7..7de0256 100644
--- a/Doc/whatsnew/3.3.rst
+++ b/Doc/whatsnew/3.3.rst
@@ -1119,7 +1119,7 @@
    +---------+-------------+--------------+-------------+
    |         |  decimal.py |   _decimal   |   speedup   |
    +=========+=============+==============+=============+
-   |   pi    |    38.89s   |    0.38s     |    100x     |
+   |   pi    |    42.02    |    0.345     |    120x     |
    +---------+-------------+--------------+-------------+
    | telco   |   172.19s   |    5.68s     |     30x     |
    +---------+-------------+--------------+-------------+
diff --git a/setup.py b/setup.py
index 7f863a4..9ddf2e9 100644
--- a/setup.py
+++ b/setup.py
@@ -1897,7 +1897,7 @@
 
     def _decimal_ext(self):
         extra_compile_args = []
-        undef_macros = ['NDEBUG']
+        undef_macros = []
         if '--with-system-libmpdec' in sysconfig.get_config_var("CONFIG_ARGS"):
             include_dirs = []
             libraries = ['mpdec']