Add <experimental/coroutine>

This patch adds the library portions of the coroutines PDTS,
which should now be supported by Clang.

llvm-svn: 303836
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 3ca9185073ef365ac7e4e027af4c939bc27cacc3
diff --git a/include/module.modulemap b/include/module.modulemap
index c354cae..737ef9a 100644
--- a/include/module.modulemap
+++ b/include/module.modulemap
@@ -501,6 +501,10 @@
       header "experimental/chrono"
       export *
     }
+    module coroutine {
+      header "experimental/coroutine"
+      export *
+    }
     module deque {
       header "experimental/deque"
       export *