Add a file to trivially disable tool building or testing

src/bootstrap/lib.rs

@@ -143,7 +143,8 @@ use std::path::{PathBuf, Path};
 use std::process::Command;
 use std::slice;
 
-use build_helper::{run_silent, run_suppressed, try_run_silent, try_run_suppressed, output, mtime};
+use build_helper::{run_silent, run_suppressed, try_run_silent, try_run_suppressed, output, mtime,
+                   BuildExpectation};
 
 use util::{exe, libdir, OutputFolder, CiEnv};
 
@@ -164,6 +165,7 @@ pub mod util;
 mod builder;
 mod cache;
 mod tool;
+mod toolstate;
 
 #[cfg(windows)]
 mod job;
@@ -542,24 +544,31 @@ impl Build {
             .join(libdir(&self.config.build))
     }
 
+    /// Runs a command, printing out nice contextual information if its build
+    /// status is not the expected one
+    fn run_expecting(&self, cmd: &mut Command, expect: BuildExpectation) {
+        self.verbose(&format!("running: {:?}", cmd));
+        run_silent(cmd, expect)
+    }
+
     /// Runs a command, printing out nice contextual information if it fails.
     fn run(&self, cmd: &mut Command) {
-        self.verbose(&format!("running: {:?}", cmd));
-        run_silent(cmd)
+        self.run_expecting(cmd, BuildExpectation::None)
     }
 
     /// Runs a command, printing out nice contextual information if it fails.
     fn run_quiet(&self, cmd: &mut Command) {
         self.verbose(&format!("running: {:?}", cmd));
-        run_suppressed(cmd)
+        run_suppressed(cmd, BuildExpectation::None)
     }
 
-    /// Runs a command, printing out nice contextual information if it fails.
-    /// Exits if the command failed to execute at all, otherwise returns its
-    /// `status.success()`.
-    fn try_run(&self, cmd: &mut Command) -> bool {
+    /// Runs a command, printing out nice contextual information if its build
+    /// status is not the expected one.
+    /// Exits if the command failed to execute at all, otherwise returns whether
+    /// the expectation was met
+    fn try_run(&self, cmd: &mut Command, expect: BuildExpectation) -> bool {
         self.verbose(&format!("running: {:?}", cmd));
-        try_run_silent(cmd)
+        try_run_silent(cmd, expect)
     }
 
     /// Runs a command, printing out nice contextual information if it fails.
@@ -567,7 +576,7 @@ impl Build {
     /// `status.success()`.
     fn try_run_quiet(&self, cmd: &mut Command) -> bool {
         self.verbose(&format!("running: {:?}", cmd));
-        try_run_suppressed(cmd)
+        try_run_suppressed(cmd, BuildExpectation::None)
     }
 
     pub fn is_verbose(&self) -> bool {