added a skeleton of the ARM backend


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28301 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/configure b/configure
index 351cdd5..b235fcd 100755
--- a/configure
+++ b/configure
@@ -3107,7 +3107,7 @@
   enableval=all
 fi;
 case "$enableval" in
-  all) TARGETS_TO_BUILD="X86 Sparc PowerPC Alpha IA64" ;;
+  all) TARGETS_TO_BUILD="X86 Sparc PowerPC Alpha IA64 ARM" ;;
   host-only)
     case "$llvm_cv_target_arch" in
       x86)     TARGETS_TO_BUILD="X86" ;;