[thrift] Erlang build tweaks

Summary: fix the Makefile to use BSD-friendly find(1) and enable conditional building of the Erlang binding.  Contributed by Dan Sully (daniel@electricrain.com).

Reviewed By: eletuchy

Test Plan: builds


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665549 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 36191f6..5d2e1fa 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -10,6 +10,10 @@
 SUBDIRS += java
 endif
 
+if ENABLE_ERLANG
+SUBDIRS += erl
+endif
+
 EXTRA_DIST = \
   cocoa \
   erl   \