Added missing cargo config

.cargo/config.toml

@@ -0,0 +1,4 @@
+[build]
+# when using osx, we need to link against some golang libraries, it did just work with this missing flags
+# from: https://github.com/golang/go/issues/42459
+rustflags = ["-C", "link-args=-framework CoreFoundation -framework Security"]

waku-sys/build.rs

@@ -1,5 +1,3 @@
-extern crate core;
-
 use std::env;
 use std::env::set_current_dir;
 use std::path::PathBuf;