THRIFT-199. perl: Let "make distclean" work when we are not using Perl

When configure is run with --without-perl, lib/perl/Makefile.am cannot
generate Makefile-perl.mk.  However, "make distclean" still runs, so
the clean-local target fails.  This version just silently does nothing
when Perl is not being used.


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@743190 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/perl/Makefile.am b/lib/perl/Makefile.am
index 0d775fa..fba568e 100644
--- a/lib/perl/Makefile.am
+++ b/lib/perl/Makefile.am
@@ -14,8 +14,10 @@
 install-exec-local: Makefile-perl.mk
 	$(MAKE) -f Makefile-perl.mk install DESTDIR=$(DESTDIR)/
 
-clean-local: Makefile-perl.mk
-	$(MAKE) -f Makefile-perl.mk clean
+clean-local:
+	if test -f Makefile-perl.mk ; then \
+		$(MAKE) -f Makefile-perl.mk clean ; \
+	fi
 	rm -f Makefile-perl.mk.old
 
 EXTRA_DIST = MANIFEST \