Add $(EXE) to various occurrences of python so it will work on Cygwin

with egcs (after setting EXE=.exe).  Patch by Norman Vine.

Modules/Makefile.pre.in

@@ -127,7 +127,7 @@ link:		$(MAINOBJ)
 		mv python$(EXE) ../python$(EXE)
 
 clean:
-		-rm -f *.o python core *~ [@,#]* *.old *.orig *.rej add2lib
+		-rm -f *.o python$(EXE) core *~ [@,#]* *.old *.orig *.rej add2lib
 
 clobber:	clean
 		-rm -f *.a tags TAGS config.c Makefile.pre
@@ -172,7 +172,7 @@ depend:
 		$(MKDEP) $(CFLAGS) `echo $(OBJS) | tr ' ' '\012' | \
 					sed 's|\(.*\)\.o|$(srcdir)/\1.c|'`
 
-.PRECIOUS:	../python
+.PRECIOUS:	../python$(EXE)
 
 glmodule.c:	$(srcdir)/cgen.py $(srcdir)/cstubs
 		python $(srcdir)/cgen.py <$(srcdir)/cstubs >glmodule.c