Add DarwinTool base class for all Darwin tools, and move AddDarwin[Sub]Arch there.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@81367 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 7cd57b9..6979408 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -1398,8 +1398,8 @@
   return 0;
 }
 
-void darwin::Link::AddDarwinArch(const ArgList &Args,
-                                 ArgStringList &CmdArgs) const {
+void darwin::DarwinTool::AddDarwinArch(const ArgList &Args,
+                                       ArgStringList &CmdArgs) const {
   // Derived from darwin_arch spec.
   CmdArgs.push_back("-arch");
 
@@ -1433,8 +1433,8 @@
   }
 }
 
-void darwin::Link::AddDarwinSubArch(const ArgList &Args,
-                                    ArgStringList &CmdArgs) const {
+void darwin::DarwinTool::AddDarwinSubArch(const ArgList &Args,
+                                          ArgStringList &CmdArgs) const {
   // Derived from darwin_subarch spec, not sure what the distinction
   // exists for but at least for this chain it is the same.
   AddDarwinArch(Args, CmdArgs);