File wallust-no-git.patch of Package wallust

diff --git a/build.rs b/build.rs
index 054326a..153fa3f 100644
--- a/build.rs
+++ b/build.rs
@@ -9,22 +9,39 @@ fn main() {
 
 /// git short sha1 and date stuff, only when wallust is at a unstable version
 fn version() -> String {
+    if !std::path::Path::new(".git").exists() {
+        return "(unknown)".to_string();
+    }
+
     use vergen_git2 as vergen;
-    let git2 = vergen::Git2Builder::default()
+    let git2 = match vergen::Git2Builder::default()
         .describe(true, false, None)
         .commit_date(true)
         .sha(true)
-        .build().unwrap();
+        .build()
+    {
+        Ok(git2) => git2,
+        Err(_) => return "(unknown)".to_string(),
+    };
 
-    vergen::Emitter::default()
-        .add_instructions(&git2).unwrap()
-        .emit_and_set().unwrap();
+    let mut emitter = vergen::Emitter::default();
+    if emitter
+        .add_instructions(&git2)
+        .and_then(|e| e.emit_and_set())
+        .is_err()
+    {
+        return "(unknown)".to_string();
+    }
 
-    let sha = std::env::var_os("VERGEN_GIT_SHA").unwrap();
-    let sha = sha.to_string_lossy();
+    let sha = match std::env::var_os("VERGEN_GIT_SHA") {
+        Some(sha) => sha.to_string_lossy().into_owned(),
+        None => return "(unknown)".to_string(),
+    };
 
-    let date = std::env::var_os("VERGEN_GIT_COMMIT_DATE").unwrap();
-    let date = date.to_string_lossy();
+    let date = match std::env::var_os("VERGEN_GIT_COMMIT_DATE") {
+        Some(date) => date.to_string_lossy().into_owned(),
+        None => return "(unknown)".to_string(),
+    };
 
     format!("({sha} {date})")
 }