[modules] When diagnosing a missing module import, suggest adding a #include if
the current language doesn't have an import syntax and we can figure out a
suitable file to include.

llvm-svn: 267802
diff --git a/clang/test/Modules/Inputs/suggest-include/module.modulemap b/clang/test/Modules/Inputs/suggest-include/module.modulemap
new file mode 100644
index 0000000..46afd7b
--- /dev/null
+++ b/clang/test/Modules/Inputs/suggest-include/module.modulemap
@@ -0,0 +1,22 @@
+module X {
+  module Empty { header "empty.h" }
+
+  exclude header "textual1.h"
+  textual header "textual2.h"
+  textual header "textual3.h"
+
+  module A { header "usetextual1.h" }
+  module B { header "usetextual2.h" }
+  module C { header "usetextual3.h" }
+  module D { header "usetextual4.h" }
+  module E { header "usetextual5.h" }
+
+  module P { private header "private1.h" }
+  module Q { private header "private2.h" }
+  module R { private header "private3.h" }
+  module S { header "useprivate1.h" export * }
+  module T { header "useprivate3.h" }
+}
+
+module Other { textual header "textual4.h" }
+