rustbuild: Point to core and collections's external benchmarks.

Author: bluss

src/libcollections/Cargo.toml

@@ -15,3 +15,7 @@ rustc_unicode = { path = "../librustc_unicode" }
 [[test]]
 name = "collectionstest"
 path = "../libcollectionstest/lib.rs"
+
+[[bench]]
+name = "collectionstest"
+path = "../libcollectionstest/lib.rs"

src/libcore/Cargo.toml

@@ -7,7 +7,12 @@ version = "0.0.0"
 name = "core"
 path = "lib.rs"
 test = false
+bench = false
 
 [[test]]
 name = "coretest"
 path = "../libcoretest/lib.rs"
+
+[[bench]]
+name = "coretest"
+path = "../libcoretest/lib.rs"