diff -r 897fe8fa14b5 setup.py
--- a/setup.py	Thu Oct 13 23:00:37 2016 -0700
+++ b/setup.py	Sat Oct 15 20:42:09 2016 +0200
@@ -230,7 +230,12 @@
         headers = [sysconfig.get_config_h_filename()]
         headers += glob(os.path.join(sysconfig.get_path('include'), "*.h"))
 
-        for ext in self.extensions[:]:
+        # The makesetup list of the statically built module objects names.
+        modobjs = [os.path.splitext(os.path.basename(p))[0] for p in
+                   re.split('(?<=\.o) +', sysconfig.get_config_var('MODOBJS'))]
+
+        removed_modules = []
+        for ext in self.extensions:
             ext.sources = [ find_module_file(filename, moddirlist)
                             for filename in ext.sources ]
             if ext.depends is not None:
@@ -242,25 +247,15 @@
             ext.depends.extend(headers)
 
             # If a module has already been built statically,
-            # don't build it here
-            if ext.name in sys.builtin_module_names:
-                self.extensions.remove(ext)
+            # don't build it here.
+            for src in ext.sources:
+                if os.path.splitext(os.path.basename(src))[0] in modobjs:
+                    removed_modules.append(ext)
+                    break
 
-        # Parse Modules/Setup and Modules/Setup.local to figure out which
-        # modules are turned on in the file.
-        remove_modules = []
-        for filename in ('Modules/Setup', 'Modules/Setup.local'):
-            input = text_file.TextFile(filename, join_lines=1)
-            while 1:
-                line = input.readline()
-                if not line: break
-                line = line.split()
-                remove_modules.append(line[0])
-            input.close()
-
-        for ext in self.extensions[:]:
-            if ext.name in remove_modules:
-                self.extensions.remove(ext)
+        if removed_modules:
+            self.extensions = [x for x in self.extensions if x not in
+                               removed_modules]
 
         # When you run "make CC=altcc" or something similar, you really want
         # those environment variables passed into the setup.py phase.  Here's
@@ -303,6 +298,12 @@
                   " detect_modules() for the module's name.")
             print()
 
+        if removed_modules:
+            print("The following modules, detected by setup.py, have been"
+                  " statically built")
+            print("instead, as configured by the Setup files:")
+            print_three_column([ext.name for ext in removed_modules])
+
         if self.failed:
             failed = self.failed[:]
             print()