Fix for PR4140: Add the start of a Linux toolchain (basically, just 
barely enough to get the given usage of -print-file-name working).

llvm-svn: 72412
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 76dc46c..d9a2c2c 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -1161,6 +1161,8 @@
     return createDragonFlyHostInfo(*this, Triple);
   case llvm::Triple::FreeBSD:
     return createFreeBSDHostInfo(*this, Triple);
+  case llvm::Triple::Linux:
+    return createLinuxHostInfo(*this, Triple);
   default:
     return createUnknownHostInfo(*this, Triple);
   }