fix the Makefile so it doesn't pollute sys.path

#4349 reviewed by Christian

Makefile.pre.in

@@ -801,7 +801,6 @@ maninstall:
 # Install the library
 PLATDIR=	plat-$(MACHDEP)
 EXTRAPLATDIR= @EXTRAPLATDIR@
-EXTRAMACHDEPPATH=@EXTRAMACHDEPPATH@
 MACHDEPS=	$(PLATDIR) $(EXTRAPLATDIR)
 XMLLIBSUBDIRS=  xml xml/dom xml/etree xml/parsers xml/sax
 LIBSUBDIRS=	tkinter site-packages test test/output test/data \

Misc/NEWS

@@ -13,6 +13,9 @@ What's New in Python 3.0 release candiate 3?
 Core and Builtins
 -----------------
 
+- Issue #4349: sys.path included a non-existent platform directory because of a
+  faulty Makefile.
+
 - Issue #3327: Don't overallocate in the modules_by_index list.
 
 - Issue #1721812:  Binary set operations and copy() returned the input type