Enable compilers other than gcc (#6)

issue: #1
Reviewed-on: http://192.168.1.227:3000/sfrembling/pallet/pulls/6
Co-authored-by: godsfryingpan <sfrembling@gmail.com>
Co-committed-by: godsfryingpan <sfrembling@gmail.com>

src/config.rs

@@ -1,5 +1,7 @@
 #[derive(serde::Deserialize, serde::Serialize, Default)]
 pub struct Config {
+    /// The C compiler to use (defaults to "gcc")
+    pub compiler: Option<String>,
     /// The name of the output binary
     pub name: String,
     /// The default build to use