Add build.rs to set ANTE_STDLIB_DIR (#116)

* Add build.rs

Since ANTE_STDLIB_DIR was not set, The compiler crashed when compiling a file other than the project root.

So I created a build script that creates the standard library directory and sets ANTE_STDLIB_DIR.

* Update mod.rs

* Update build.rs

* Update build.rs

Cargo.toml

@@ -3,6 +3,7 @@ name = "ante"
 version = "0.1.1"
 authors = ["Jake Fecher <[email protected]>"]
 edition = "2018"
+build = "build.rs"
 
 [lib]
 name = "ante"

build.rs

@@ -0,0 +1,9 @@
+use std::env;
+
+fn main() -> std::io::Result<()> {
+    if option_env!("ANTE_STDLIB_DIR").is_none() {
+        let cur_dir = env::current_dir()?;
+        println!("cargo:rustc-env=ANTE_STDLIB_DIR={}/stdlib", cur_dir.to_str().unwrap());
+    }
+    Ok(())
+}

src/util/mod.rs

@@ -73,14 +73,7 @@ pub fn binary_name(module_name: &str) -> String {
 pub fn stdlib_dir() -> PathBuf {
     match option_env!("ANTE_STDLIB_DIR") {
         Some(env) => std::fs::canonicalize(env).unwrap(),
-        None => {
-            let mut path = PathBuf::from(file!());
-            path.pop();
-            path.pop();
-            path.pop();
-            path.push("stdlib");
-            path.canonicalize().unwrap()
-        }
+        None => panic!("ANTE_STDLIB_DIR is not set"),
     }
 }