Removed unwrap()s, refactored iterator, removed memleak

build.rs

@@ -1,17 +1,17 @@
 extern crate cc;
 
 use std::fs;
+use std::io::Result;
 
-fn main() {
+fn main() -> Result<()> {
     // This builds gromacs' xdrfile library
-    let source_files: Vec<_> = fs::read_dir("external/xdrfile/src")
-        .unwrap()
-        .map(|f| f.unwrap())
-        .map(|f| f.path())
-        .collect();
+    let source_files = fs::read_dir("external/xdrfile/src")?
+        .map(|r| r.map(|f| f.path()))
+        .collect::<Result<Vec<_>>>()?;
     cc::Build::new()
         .files(source_files)
         .include("external/xdrfile/include")
         .warnings(false)
-        .compile("libxdrfile.a")
+        .compile("libxdrfile.a");
+    Ok(())
 }