Need prebuilt linker executable for host Bionic.

ART runs some tests on host using linux_bionic (cf.
ab/git_master-art-host). On device Bionic binaries come from its APEX,
but on host they have to be supplied separately. Since they're not part
of the SDK they are instead provided through a `module_export` module,
which is technically similar to `sdk` in the way it produces prebuilt
snapshots.

Test: art/test/testrunner/run_build_test_target.py art-linux-bionic-x64
  on a master-art branch using snapshot built from runtime-module-sdk
  and runtime-module-host-exports
Bug: 152255951
Change-Id: I143b5412f7284f42c7e8be6cecc5ec96f1dc70f3

1 files changed, 10 insertions, 0 deletions

diff --git a/apex/Android.bp b/apex/Android.bp
index 8c8853ff6..ce9d82bdf 100644
--- a/apex/Android.bp
+++ b/apex/Android.bp
@@ -62,3 +62,13 @@ sdk {
         "crtend_so",
     ],
 }
+
+module_exports {
+    name: "runtime-module-host-exports",
+    defaults: ["linux_bionic_supported"],
+    device_supported: false,
+
+    native_binaries: [
+        "linker",
+    ],
+}