lldb launch fails due to negative line offsets in frames

It appears that lldb produces frames with -1 as the line offset. MITextPosition does not handle negative integers and launch fails.

The test machine was Ubuntu 14.04.

The config file used:
<PipeLaunchOptions xmlns="http://schemas.microsoft.com/vstudio/MDDDebuggerOptions/2014" PipePath="F:\MIEngineWorkspace\plink.exe" PipeArguments="-i F:\MIEngineWorkspace\private.ppk wiktor@10.127.84.95 -batch -t lldb-mi-3.6 --interpreter mi" ExePath="~/Shared/TargetApp/targetapp" TargetArchitecture="x86_64" MIMode="lldb">

Resulting output
MS_MIDebug: (1439629) ->1005-thread-info MS_MIDebug: (1439629) -> MS_MIDebug: (1439629) ->1005^done,threads=[{id="1",target-id="targetapp",frame={level="0",addr="0x00400df1",func="main",args=[],file="main.cpp",fullname="/home//wiktor/Shared/TargetApp/main.cpp",line="25"},frame={level="1",addr="0x7f7f7079dec5",func="__libc_start_main",args=[],file="??",fullname="??",line="-1"},frame={level="2",addr="0x00400ca9",func="??",args=[],file="??",fullname="??",line="-1"},state="stopped"}]

Resulting exception

    Microsoft.MICore.dll!MICore.Debugger.ParseUint(string str, bool throwOnError) Line 1214 C#
Microsoft.MICore.dll!MICore.ConstValue.ToUint.get() Line 246    C#
Microsoft.MICore.dll!MICore.ResultValue.TryFindUint(string name) Line 110   C#
Microsoft.MIDebugEngine.dll!Microsoft.MIDebugEngine.MITextPosition.TryParse(MICore.TupleValue miTuple) Line 43  C#
Microsoft.MIDebugEngine.dll!Microsoft.MIDebugEngine.ThreadCache.CreateContext(MICore.TupleValue frame) Line 172 C#
Microsoft.MIDebugEngine.dll!Microsoft.MIDebugEngine.ThreadCache.CollectThreadsInfo(int cxtThreadId) Line 239    C#

`

Start with MITextPosition.TryParse and the ParseUint call shown in the stack trace, then inspect how ThreadCache.CreateContext consumes the parsed frame. Reproduce the LLDB output containing line="-1" if possible. Done means frames with negative line offsets no longer cause launch parsing to fail.