Implement <span>. Reviewed as https://reviews.llvm.org/D49338

llvm-svn: 337804
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 8a0794b722bd42d12c58295c69b659e79c73a903
diff --git a/include/module.modulemap b/include/module.modulemap
index 70f82a7..e17c3a2 100644
--- a/include/module.modulemap
+++ b/include/module.modulemap
@@ -559,6 +559,10 @@
       header "experimental/set"
       export *
     }
+    module span {
+      header "span"
+      export *
+    }
     module string {
       header "experimental/string"
       export *