cmTarget: Make the source files depend on the config.

Disallow the use of config-specific source files with
the Visual Studio and Xcode generators. They don't have
any way to represent the condition currently.

Use the same common-config API in cmQtAutoGenerators. While
it accepts config-specific files, it doesn't have to support
multiple configurations yet.

Loop over the configs in cmTargetTraceDependencies
and cmGlobalGenerator::WriteSummary and consume all source
files.

Loop over the configs in cmComputeTargetDepends and compute the
object library dependencies for each config.

Source/cmExtraSublimeTextGenerator.cxx

@@ -238,7 +238,8 @@ void cmExtraSublimeTextGenerator::
       cmGeneratorTarget *gtgt = this->GlobalGenerator
                                     ->GetGeneratorTarget(target);
       std::vector<cmSourceFile*> sourceFiles;
-      target->GetSourceFiles(sourceFiles);
+      target->GetSourceFiles(sourceFiles,
+                             makefile->GetSafeDefinition("CMAKE_BUILD_TYPE"));
       std::vector<cmSourceFile*>::const_iterator sourceFilesEnd =
         sourceFiles.end();
       for (std::vector<cmSourceFile*>::const_iterator iter =