Add support of the next Ubuntu (Ubuntu 19.04 - Disco Dingo)

llvm-svn: 346103
diff --git a/clang/lib/Driver/Distro.cpp b/clang/lib/Driver/Distro.cpp
index fbfc041..eb537c8 100644
--- a/clang/lib/Driver/Distro.cpp
+++ b/clang/lib/Driver/Distro.cpp
@@ -51,6 +51,7 @@
                       .Case("artful", Distro::UbuntuArtful)
                       .Case("bionic", Distro::UbuntuBionic)
                       .Case("cosmic", Distro::UbuntuCosmic)
+                      .Case("disco", Distro::UbuntuDisco)
                       .Default(Distro::UnknownDistro);
     if (Version != Distro::UnknownDistro)
       return Version;