EXEEXT for a few more targets, dropbearmulti in particular for Cygwin

From William K. Foster.

Makefile.in

@@ -116,7 +116,7 @@ ifeq ($(STATIC), 1)
 endif
 ifeq ($(MULTI), 1)
-	TARGETS=dropbearmulti
+	TARGETS=dropbearmulti$(EXEEXT)
 else
 	TARGETS=$(PROGRAMS)
 endif
@@ -133,14 +133,14 @@ strip: $(TARGETS)
 install: $(addprefix inst_, $(TARGETS))
-insmultidropbear: dropbearmulti
+insmultidropbear: dropbearmulti$(EXEEXT)
 	$(INSTALL) -d $(DESTDIR)$(sbindir)
 	-rm -f $(DESTDIR)$(sbindir)/dropbear$(EXEEXT)
 	-ln -s $(bindir)/dropbearmulti$(EXEEXT) $(DESTDIR)$(sbindir)/dropbear$(EXEEXT) 
 	$(INSTALL) -d $(DESTDIR)$(mandir)/man8
 	$(INSTALL) -m 644 $(srcdir)/dropbear.8  $(DESTDIR)$(mandir)/man8/dropbear.8
-insmulti%: dropbearmulti
+insmulti%: dropbearmulti$(EXEEXT)
 	$(INSTALL) -d $(DESTDIR)$(bindir)
 	-rm -f $(DESTDIR)$(bindir)/$*$(EXEEXT) 
 	-ln -s $(bindir)/dropbearmulti$(EXEEXT) $(DESTDIR)$(bindir)/$*$(EXEEXT) 
@@ -220,8 +220,9 @@ sizes: dropbear
 clean: ltc-clean ltm-clean thisclean
 thisclean:
-	-rm -f dropbear dbclient dropbearkey dropbearconvert scp scp-progress \
-			dropbearmulti *.o *.da *.bb *.bbg *.prof
+	-rm -f dropbear$(EXEEXT) dbclient$(EXEEXT) dropbearkey$(EXEEXT) \
+			dropbearconvert$(EXEEXT) scp$(EXEEXT) scp-progress$(EXEEXT) \
+			dropbearmulti$(EXEEXT) *.o *.da *.bb *.bbg *.prof
 distclean: clean tidy
 	-rm -f config.h