Create a LinuxTargetInfo on ARM. This make clang correctly expand
__USER_LABEL_PREFIX__.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@105771 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index a6548c4..fb58739 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -2323,6 +2323,8 @@
   case llvm::Triple::arm:
   case llvm::Triple::thumb:
     switch (os) {
+    case llvm::Triple::Linux:
+      return new LinuxTargetInfo<ARMTargetInfo>(T);
     case llvm::Triple::Darwin:
       return new DarwinARMTargetInfo(T);
     case llvm::Triple::FreeBSD: