Features: Add COMPILE_FEATURES generator expression.

Allow setting build properties based on the features available
for a target.  The availability of features is determined at
generate-time by evaluating the link implementation.

Ensure that the <LANG>_STANDARD determined while evaluating
COMPILE_FEATURES in the link implementation is not lower than that
provided by the INTERFACE of the link implementation.  This is
similar to handling of transitive properties such as
POSITION_INDEPENDENT_CODE.

1 files changed, 21 insertions, 0 deletions

diff --git a/Tests/CompileFeatures/genex_test.cpp b/Tests/CompileFeatures/genex_test.cpp
new file mode 100644
index 0000000..ca38883
--- /dev/null
+++ b/Tests/CompileFeatures/genex_test.cpp
@@ -0,0 +1,21 @@
+
+#if !HAVE_OVERRIDE_CONTROL
+#error "Expect override control feature"
+#else
+
+struct A
+{
+  virtual int getA() { return 7; }
+};
+
+struct B final : A
+{
+  int getA() override { return 42; }
+};
+
+#endif
+
+int main()
+{
+
+}