ARM: support .watchos_version_min and .tvos_version_min.

These MachO file directives are used by linkers and other tools to provide
compatibility information, much like the existing .ios_version_min and
.macosx_version_min.

llvm-svn: 251569
diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index a6c4e28..2f06415 100644
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -369,6 +369,8 @@
 void MCAsmStreamer::EmitVersionMin(MCVersionMinType Kind, unsigned Major,
                                    unsigned Minor, unsigned Update) {
   switch (Kind) {
+  case MCVM_WatchOSVersionMin:    OS << "\t.watchos_version_min"; break;
+  case MCVM_TvOSVersionMin:       OS << "\t.tvos_version_min"; break;
   case MCVM_IOSVersionMin:        OS << "\t.ios_version_min"; break;
   case MCVM_OSXVersionMin:        OS << "\t.macosx_version_min"; break;
   }