Add test for pipelined builds

This makes sure that building a crate with an rmeta dependency is viable as a
linkable crate.

Author: jsgf

src/test/run-make/pipelined/Makefile

@@ -0,0 +1,15 @@
+-include ../../run-make-fulldeps/tools.mk
+
+O=$(TMPDIR)
+
+all: $O/main
+	$O/main
+
+$O/main: $O/libmiddle.rlib $O/libleaf.rlib
+	$(RUSTC) main.rs --extern middle=$O/libmiddle.rlib -Ldependency=$O
+
+$O/libmiddle.rlib: middle.rs $O/libleaf.rmeta
+	$(RUSTC) --emit link middle.rs --extern leaf=$O/libleaf.rmeta
+
+$O/libleaf.rlib $O/libleaf.rmeta: leaf.rs
+	$(RUSTC) --emit metadata,link leaf.rs

src/test/run-make/pipelined/leaf.rs

@@ -0,0 +1,25 @@
+#![crate_type = "rlib"]
+
+pub static FOO: &str = "this is a static";
+
+#[derive(Debug)]
+pub struct Plain {
+    pub a: u32,
+    pub b: u32,
+}
+
+#[derive(Debug)]
+pub struct GenericStruct<A> {
+    pub a: A,
+    pub b: Option<A>,
+}
+
+pub fn simple(a: u32, b: u32) -> u32 {
+    let c = a + b;
+    println!("simple {} + {} => {}", a, b, c);
+    c
+}
+
+pub fn generic<D: std::fmt::Debug>(d: D) {
+    println!("generically printing {:?}", d);
+}

src/test/run-make/pipelined/main.rs

@@ -0,0 +1,9 @@
+#![crate_type = "bin"]
+
+fn main() {
+    middle::do_a_thing();
+
+    println!("middle::BAR {}", middle::BAR);
+
+    assert_eq!(middle::simple(2, 3), 5);
+}

src/test/run-make/pipelined/middle.rs

@@ -0,0 +1,22 @@
+#![crate_type = "rlib"]
+
+extern crate leaf;
+
+pub static BAR: &str = leaf::FOO;
+
+pub use leaf::simple;
+
+pub fn do_a_thing() {
+    let s = leaf::GenericStruct {
+        a: "hello",
+        b: Some("world")
+    };
+
+    let u = leaf::GenericStruct {
+        a: leaf::Plain { a: 1, b: 2 },
+        b: None
+    };
+
+    leaf::generic(s);
+    leaf::generic(u);
+}