Fix quoting in configure. Patch by Krzysztof Parzyszek!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171108 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index 0395931..08e7f32 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -511,10 +511,10 @@
 case "$enableval" in
   yes) AC_SUBST(ENABLE_CLANG_REWRITER,[1]) ;;
   no)  
-    if test clang_arcmt != "no" ; then
+    if test ${clang_arcmt} != "no" ; then
       AC_MSG_ERROR([Cannot enable clang ARC Migration Tool while disabling rewriter.])
     fi
-    if test clang_static_analyzer != "no" ; then
+    if test ${clang_static_analyzer} != "no" ; then
       AC_MSG_ERROR([Cannot enable clang static analyzer while disabling rewriter.])
     fi
     AC_SUBST(ENABLE_CLANG_REWRITER,[0])