Improve error when n2/ninja missing

Author: dae

build/runner/src/build.rs

@@ -77,7 +77,9 @@ pub fn run_build(args: BuildArgs) {
     }
 
     // run build
-    let mut status = command.status().expect("ninja not installed");
+    let Ok(mut status) = command.status() else {
+        panic!("\nn2 and ninja missing/failed. did you forget 'bash tools/install-n2'?");
+    };
     if !status.success() && Instant::now().duration_since(start_time).as_secs() < 3 {
         // if the build fails quickly, there's a reasonable chance that build.ninja
         // references a file that has been renamed/deleted. We currently don't

docs/linux.md

@@ -19,13 +19,10 @@ Users on ARM64, see the notes at the bottom of this file before proceeding.
 **Ensure some basic tools are installed**:
 
 ```
-$ sudo apt install bash grep findutils curl gcc g++ make git rsync ninja-build
+$ sudo apt install bash grep findutils curl gcc g++ make git rsync
 ```
 
 - The 'find' utility is 'findutils' on Debian.
-- Your distro may call the package 'ninja' instead of 'ninja-build', or it
-  may not have a version new enough - if so, install from the zip mentioned in
-  development.md.
 
 ## Missing Libraries