Statically provide the release commit hash and date by replacing the
placeholder values within the ebuild.

Author: Lucio Sauer <watermanpaint@posteo.net>
--- a/build.rs
+++ b/build.rs
@@ -1,25 +1,11 @@
-use std::process::Command;
-
 fn main() {
-    let hash = Command::new("git")
-        .args(["rev-parse", "--short", "HEAD"])
-        .env("GIT_CONFIG_GLOBAL", "/dev/null")
-        .output()
-        .map(|o| String::from_utf8(o.stdout).unwrap());
-    let date = Command::new("git")
-        .args(["log", "--pretty=format:'%ad'", "-n1", "--date=short"])
-        .env("GIT_CONFIG_GLOBAL", "/dev/null")
-        .output()
-        .map(|o| String::from_utf8(o.stdout).unwrap());
-    if let (Ok(hash), Ok(date)) = (hash, date) {
-        let ver = format!(
-            "{} (commit {} {})",
-            env!("CARGO_PKG_VERSION"),
-            hash.trim(),
-            date.trim_matches('\'')
-        );
-        println!("cargo:rustc-env=VERSION={ver}");
-    } else {
-        println!("cargo:rustc-env=VERSION={}", env!("CARGO_PKG_VERSION"));
-    }
+    let hash = String::from("%COMMIT%");
+    let date = String::from("%DATE%");
+    let ver = format!(
+        "{} (commit {} {})",
+        env!("CARGO_PKG_VERSION"),
+        hash.trim(),
+        date.trim_matches('\'')
+    );
+    println!("cargo:rustc-env=VERSION={ver}");
 }