fix: 没有应用程序时 build.rs 溢出

Signed-off-by: YdrMaster <ydrml@hotmail.com>

Author: YdrMaster

os2-ref/build.rs

@@ -36,7 +36,9 @@ _num_app:
     for i in 0..apps.len() {
         writeln!(f, r#"    .quad app_{}_start"#, i)?;
     }
-    writeln!(f, r#"    .quad app_{}_end"#, apps.len() - 1)?;
+    if !apps.is_empty() {
+        writeln!(f, r#"    .quad app_{}_end"#, apps.len() - 1)?;
+    }
 
     for (idx, app) in apps.iter().enumerate() {
         println!("app_{}: {}", idx, app);

os3-ref/build.rs

@@ -39,7 +39,9 @@ _num_app:
     for i in 0..apps.len() {
         writeln!(f, r#"    .quad app_{}_start"#, i)?;
     }
-    writeln!(f, r#"    .quad app_{}_end"#, apps.len() - 1)?;
+    if !apps.is_empty() {
+        writeln!(f, r#"    .quad app_{}_end"#, apps.len() - 1)?;
+    }
 
     for (idx, app) in apps.iter().enumerate() {
         println!("app_{}: {}", idx, app);

os4-ref/build.rs

@@ -39,7 +39,9 @@ _num_app:
     for i in 0..apps.len() {
         writeln!(f, r#"    .quad app_{}_start"#, i)?;
     }
-    writeln!(f, r#"    .quad app_{}_end"#, apps.len() - 1)?;
+    if !apps.is_empty() {
+        writeln!(f, r#"    .quad app_{}_end"#, apps.len() - 1)?;
+    }
 
     for (idx, app) in apps.iter().enumerate() {
         println!("app_{}: {}", idx, app);

os5-ref/build.rs

@@ -40,7 +40,9 @@ _num_app:
     for i in 0..apps.len() {
         writeln!(f, r#"    .quad app_{}_start"#, i)?;
     }
-    writeln!(f, r#"    .quad app_{}_end"#, apps.len() - 1)?;
+    if !apps.is_empty() {
+        writeln!(f, r#"    .quad app_{}_end"#, apps.len() - 1)?;
+    }
 
     writeln!(
         f,