diff --git a/rebar.config b/rebar.config
index 9a8dc93..701591c 100644
--- a/rebar.config
+++ b/rebar.config
@@ -1,7 +1,7 @@
 %%-*- mode: erlang -*-
 %% ex: ft=erlang ts=4 sw=4 et
 
-{require_otp_vsn, "R1[456]"}.
+{require_otp_vsn, "R1[567]"}.
 
 {cover_enabled, true}.
 
@@ -27,7 +27,7 @@
             %strict_validation
             ]}.
 
-{xref_checks, [undefined_function_calls]}.
+{xref_checks, [undefined_function_calls, deprecated_function_calls]}.
 
 {deps, [
         {lager, "2.*", {git, "git://github.com/basho/lager", {branch, "master"}}}
@@ -36,7 +36,7 @@
 {port_specs, [{"priv/wterl.so", ["c_src/*.c"]}]}.
 
 {port_env, [
-            {"DRV_CFLAGS",  "$DRV_CFLAGS -Werror -I c_src/system/include"},
+            {"DRV_CFLAGS",  "$DRV_CFLAGS -fPIC -g -Wall -Wextra -Werror -I c_src/system/include"},
             {"DRV_LDFLAGS", "$DRV_LDFLAGS -Wl,-rpath,lib/wterl/priv:priv -Lc_src/system/lib -lwiredtiger"}
            ]}.