Fix Clang-tidy readability-redundant-string-cstr warnings

Reviewers: zturner, labath

Subscribers: tberghammer, danalbert, lldb-commits
    
Differential Revision: https://reviews.llvm.org/D26233

llvm-svn: 285855
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp b/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp
index 0956814..ac6e93c 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp
@@ -1149,7 +1149,7 @@
   GlobalVariable *persistent_global = new GlobalVariable(
       (*m_module), alloc->getType(), false, /* not constant */
       GlobalValue::ExternalLinkage, NULL,   /* no initializer */
-      alloc->getName().str().c_str());
+      alloc->getName().str());
 
   // What we're going to do here is make believe this was a regular old external
   // variable.  That means we need to make the metadata valid.