THRIFT-905: hook haskell into autoconf

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@1001823 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 56c4e97..3c95f24 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -43,6 +43,10 @@
 SUBDIRS += rb
 endif
 
+if WITH_HASKELL
+SUBDIRS += hs
+endif
+
 if WITH_PERL
 SUBDIRS += perl
 endif
@@ -55,7 +59,6 @@
 # so they will end up in our release tarballs.
 EXTRA_DIST = \
   cocoa \
-  hs \
   ocaml \
   php \
   erl \