Fixed a potential crasher if the frame is not
avalable when a global variable is looked up.
In ClangExpressionDeclMap, a frame should usually
be available.

llvm-svn: 146066
diff --git a/lldb/source/Expression/ClangExpressionDeclMap.cpp b/lldb/source/Expression/ClangExpressionDeclMap.cpp
index d879f19..08a5074 100644
--- a/lldb/source/Expression/ClangExpressionDeclMap.cpp
+++ b/lldb/source/Expression/ClangExpressionDeclMap.cpp
@@ -2539,7 +2539,7 @@
                 return;
             }
         }
-        else if (target)
+        else if (frame && target)
         {
             var = FindGlobalVariable (*target,
                                       module_sp,