Update to latest rebar which passes environment through to port compi…

…lation

rebar.config

@@ -1,16 +1,14 @@
 %% -*- mode: erlang;erlang-indent-level: 2;indent-tabs-mode: nil -*-
+{erl_opts, [debug_info]}.
+
 {so_specs,
  [{"priv/bcrypt_nif.so",
    ["c_src/blowfish.c", "c_src/bcrypt.c", "c_src/bcrypt_nif.c"]}]}.
 
-{erl_opts, [debug_info]}.
-
-% This ugly hack is necessary because rebar's supported pre and post hooks
-% don't include the environment vars necessary for building port programs.
-{port_pre_script, {"echo -e \"#!/bin/sh\\n$CC $CFLAGS $ERL_CFLAGS "
-                   "c_src/bcrypt_port.c c_src/bcrypt.o c_src/blowfish.o "
-                   "$LDFLAGS $ERL_LDFLAGS -lpthread "
-                   "-o priv/bcrypt\" > build_port.sh",
-                   "build_port.sh"}}.
-{pre_hooks,  [{clean, "rm -f priv/bcrypt build_port.sh"}]}.
-{post_hooks, [{compile, "sh build_port.sh"}]}.
+{post_hooks,
+ [{clean, "rm -f priv/bcrypt"},
+  {compile,
+   "$CC $CFLAGS $ERL $ERL_CFLAGS "
+   "c_src/bcrypt_port.c c_src/bcrypt.o c_src/blowfish.o "
+   "$LDFLAGS $ERL_LDFLAGS -lpthread "
+   "-o priv/bcrypt"}]}.