More pre-2.3 build tweaks for the OS/2 EMX port:

- separate the building of the core from the wrapper executables and the
  external modules (.PYDs), based on the Py_BUILD_CORE define;

- clean up the generated import library definiton (.DEF file) to remove
  references to a number of non-static symbols that aren't part of the
  Python API and which shouldn't be exported by the core DLL;

- compile the release build with -fomit-frame-pointer, for a small
  performance gain;

- make "make clean" remove byte compiled Python library files.
diff --git a/PC/os2emx/pyconfig.h b/PC/os2emx/pyconfig.h
index 209d161..206223f 100644
--- a/PC/os2emx/pyconfig.h
+++ b/PC/os2emx/pyconfig.h
@@ -26,6 +26,18 @@
 /*#define Py_DEBUG 1*/
 #endif
 
+/* if building an extension or wrapper executable,
+ * mark Python API symbols "extern" so that symbols
+ * imported from the Python core DLL aren't duplicated.
+ */
+#ifdef Py_BUILD_CORE
+#  define PyAPI_FUNC(RTYPE)     RTYPE
+#else
+#  define PyAPI_FUNC(RTYPE)     extern RTYPE
+#endif
+#define PyAPI_DATA(RTYPE)       extern RTYPE
+#define PyMODINIT_FUNC  void
+
 /* Use OS/2 flavour of threads */
 #define WITH_THREAD	1
 #define OS2_THREADS	1