Add strip_dir argument to the single call to .object_filenames(), to

prevent creating files such as build/lib.whatever/Modules/foo.o
    when given a source filename such as Modules/foo.c.

Lib/distutils/ccompiler.py

@@ -366,6 +366,7 @@ class CCompiler:
         """
         # Get the list of expected output (object) files 
         objects = self.object_filenames (sources,
+                                         strip_dir=1,
                                          output_dir=output_dir)
 
         if self.force: