cmListFileCache: Implement cmListFileBacktrace ctor/dtor out-of-line

Source/cmListFileCache.cxx

@@ -398,6 +398,17 @@ bool cmListFileParser::AddArgument(cmListFileLexer_Token* token,
     }
 }
 
+cmListFileBacktrace::cmListFileBacktrace(cmState::Snapshot snapshot,
+                                         cmCommandContext const& cc)
+  : Context(cc)
+  , Snapshot(snapshot)
+{
+}
+
+cmListFileBacktrace::~cmListFileBacktrace()
+{
+}
+
 void cmListFileBacktrace::PrintTitle(std::ostream& out) const
 {
   if (!this->Snapshot.IsValid())

Source/cmListFileCache.h

@@ -90,10 +90,8 @@ class cmListFileBacktrace
 {
   public:
     cmListFileBacktrace(cmState::Snapshot snapshot = cmState::Snapshot(),
-                        cmCommandContext const& cc = cmCommandContext())
-      : Context(cc), Snapshot(snapshot)
-    {
-    }
+                        cmCommandContext const& cc = cmCommandContext());
+    ~cmListFileBacktrace();
 
     void PrintTitle(std::ostream& out) const;
     void PrintCallStack(std::ostream& out) const;