cmTarget: Allow transitive evaluation of SOURCES property.

Extend the cmGeneratorExpressionDAGChecker with an interface
returning the name of the top target.  Use that to determine
when there is a DAG violation, as required by the RunCMake.Languages
tests.

1 files changed, 7 insertions, 0 deletions

diff --git a/Tests/SourcesProperty/main.cpp b/Tests/SourcesProperty/main.cpp
new file mode 100644
index 0000000..ae4f305
--- /dev/null
+++ b/Tests/SourcesProperty/main.cpp
@@ -0,0 +1,7 @@
+
+#include "iface.h"
+
+int main(int argc, char** argv)
+{
+  return iface();
+}