[Triple] Add a "macos" OS type that acts as a synonym for "macosx"

The "macosx" OS type is still the canonical type. In the future "macos" will
become the canonical OS type (but we will still support "macosx").

rdar://27043820

Differential Revision: https://reviews.llvm.org/D32748

llvm-svn: 302011
diff --git a/llvm/lib/Support/Triple.cpp b/llvm/lib/Support/Triple.cpp
index f3a654d..eb81089 100644
--- a/llvm/lib/Support/Triple.cpp
+++ b/llvm/lib/Support/Triple.cpp
@@ -459,7 +459,7 @@
     .StartsWith("kfreebsd", Triple::KFreeBSD)
     .StartsWith("linux", Triple::Linux)
     .StartsWith("lv2", Triple::Lv2)
-    .StartsWith("macosx", Triple::MacOSX)
+    .StartsWith("macos", Triple::MacOSX)
     .StartsWith("netbsd", Triple::NetBSD)
     .StartsWith("openbsd", Triple::OpenBSD)
     .StartsWith("solaris", Triple::Solaris)
@@ -984,6 +984,8 @@
   StringRef OSTypeName = getOSTypeName(getOS());
   if (OSName.startswith(OSTypeName))
     OSName = OSName.substr(OSTypeName.size());
+  else if (getOS() == MacOSX)
+    OSName.consume_front("macos");
 
   parseVersionFromName(OSName, Major, Minor, Micro);
 }