libftdi: fix cross-compile (#369149)

Author: misuzu

pkgs/development/libraries/libftdi/default.nix

@@ -27,7 +27,9 @@ stdenv.mkDerivation rec {
 
   propagatedBuildInputs = [ libusb-compat-0_1 ];
 
-  configureFlags = lib.optional (!stdenv.hostPlatform.isDarwin) "--with-async-mode";
+  configureFlags = [
+    "ac_cv_prog_HAVELIBUSB=${lib.getExe' (lib.getDev libusb-compat-0_1) "libusb-config"}"
+  ] ++ lib.optional (!stdenv.hostPlatform.isDarwin) "--with-async-mode";
 
   # allow async mode. from ubuntu. see:
   #   https://bazaar.launchpad.net/~ubuntu-branches/ubuntu/trusty/libftdi/trusty/view/head:/debian/patches/04_async_mode.diff