Added a "--debug" option to the "expression" command. 

Cleaned up ClangUserExpression::Evaluate() to have only one variant that takes a "const EvaluateExpressionOptions& options" instead of taking many arguments.

The "--debug" option is designed to allow you to debug your expression by stopping at the first instruction (it enables --ignore-breakpoints=true and --unwind-on-error=false) and allowing you to step through your JIT code. It needs to be more integrated with the thread plan, so I am checking this in so Jim Ingham can make it happen.



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@194009 91177308-0d34-0410-b5e6-96231b3b80d8
<rdar://problem/15367406>

Fixed a case where on darwin, after recent compiler changes a few months ago, we could not execute dlopen() in an expression, or use "process load".

The issue was some compiler option default values changed. We now override these settings to get the old behavior back.



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@194012 91177308-0d34-0410-b5e6-96231b3b80d8