When Swift imports C structs, it synthesizes an initializer that takes no arguments and zero-initializes the C struct.
When C++ interop is enabled, Clang treats all C structs as if they were C++ structs. This means that some of the C structs will get a default constructor implicitly generated by Clang. This implicit default constructor will not zero-initialize trivial fields of the struct.
This is a common source of confusion and subtle bugs for developers who try to enable C++ interop in existing projects that use C interop and rely on zero-initialization of C structs.
rdar://115909532
The use of 'nocapture' for parameters and return values is incorrect for C++ types, as they can actually capture a pointer into its own value (e.g. std::string in libstdc++)
rdar://115062687
These tests fail when run locally on Apple Silicon Macs because they specify `-target x86_64-apple-macosx10.9` instead of `%target-cpu-apple-macosx10.9`. Tests that have architecture specific output should require that architecture.
`Swift` is the name of the Swift standard library module. Creating another module with this name breaks assumptions in the compiler and caused these two tests to fail.
