rustbuild: Add `make check` and a check target

We'll tack on more steps here later

src/bootstrap/build/step.rs

@@ -53,11 +53,19 @@ pub struct Step<'a> {
             // with braces are unstable so we just pick something that works.
             (llvm, Llvm { _dummy: () }),
             (compiler_rt, CompilerRt { _dummy: () }),
+
+            // Steps for various pieces of documentation that we can generate,
+            // the 'doc' step is just a pseudo target to depend on a bunch of
+            // others.
             (doc, Doc { stage: u32 }),
             (doc_book, DocBook { stage: u32 }),
             (doc_nomicon, DocNomicon { stage: u32 }),
             (doc_style, DocStyle { stage: u32 }),
             (doc_standalone, DocStandalone { stage: u32 }),
+
+            // Steps for running tests. The 'check' target is just a pseudo
+            // target to depend on a bunch of others.
+            (check, Check { stage: u32, compiler: Compiler<'a> }),
         }
     }
 }
@@ -175,6 +183,7 @@ fn add_steps<'a>(build: &'a Build,
             "doc-nomicon" => targets.push(host.doc_nomicon(stage)),
             "doc-book" => targets.push(host.doc_book(stage)),
             "doc" => targets.push(host.doc(stage)),
+            "check" => targets.push(host.check(stage, compiler)),
             _ => panic!("unknown build target: `{}`", step),
         }
     }
@@ -240,6 +249,9 @@ pub fn deps(&self, build: &'a Build) -> Vec<Step<'a>> {
                 vec![self.doc_book(stage), self.doc_nomicon(stage),
                      self.doc_style(stage), self.doc_standalone(stage)]
             }
+            Source::Check { stage, compiler: _ } => {
+                vec![]
+            }
         }
     }
 }

src/bootstrap/mk/Makefile.in

@@ -36,3 +36,5 @@ book:
 	$(Q)$(BOOTSTRAP) --step doc-book
 standalone-docs:
 	$(Q)$(BOOTSTRAP) --step doc-standalone
+check:
+	$(Q)$(BOOTSTRAP) --step check