THRIFT-646. erlang: Fix build on machines without Erlang

AC_ERLANG_SUBST_LIB_DIR aborts configure if erlc cannot be found.  Just
skip that and all of the other install stuff if we don't have Erlang.

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@988720 13f79535-47bb-0310-9956-ffa450edef68
1 file changed