rebar.config

{port_env,
 [{"darwin", "LDFLAGS", "-framework CoreFoundation -framework CoreServices -flat_namespace -undefined dynamic_lookup -dynamiclib -lstdc++"},
  {"darwin", "CC", "gcc"},
  {"darwin", "CFLAGS", "-O3 -fPIC -fno-common -Wall -Ic_src/ed25519 -Ic_src/ed25519/nacl_includes -Ic_src/ed25519/additions"},
  {"linux", "CFLAGS", "$CFLAGS -Ic_src/ed25519 -Ic_src/ed25519/nacl_includes -Ic_src/ed25519/additions"},
  {"linux", "LDFLAGS", "-shared"}
 ]
}.

{port_specs,
 [{"darwin", "priv/curve25519_drv.so", ["c_src/curve25519-donna-c64.c",
						             "c_src/ed25519/*.c",
						             "c_src/ed25519/nacl_sha512/*.c",
						             "c_src/ed25519/additions/*.c",
						             "c_src/curve25519_nif.c"]},
  {"linux", "priv/curve25519_drv.so", ["c_src/curve25519-donna-c64.c",
						             "c_src/ed25519/*.c",
						             "c_src/ed25519/nacl_sha512/*.c",
						             "c_src/ed25519/additions/*.c",
						             "c_src/curve25519_nif.c"]}
  ]}.

{plugins, [pc]}.
{provider_hooks, [
  {pre, [
    {compile, {pc, compile}},
    {clean, {pc, clean}}
   ]}]}.