Rather than injecting `CMakeLists.txt` files into each target's
`SOURCES`, teach the generators to add them during generation using
dedicated code. This avoids mutating the original targets, and avoids
polluting `$<TARGET_PROPERTY:foo,SOURCES>` with generator-specific
content.
This also avoids listing the `CMakeLists.txt` sources in the results of
`CMAKE_DEBUG_TARGET_PROPERTIES==SOURCES` so the `RunCMake.TargetSources`
test no longer needs a separate case for IDEs.
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.
Brad King