[Bug target/83307] Miscompilation of range_for with initializer_list in constructors on MacOS (works on Linux)

[greenc at fnal dot gov]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83307

--- Comment #1 from Chris Green <greenc at fnal dot gov> ---
Verified as continuing to fail on MacOS High Sierra (XCode 9.2 / 9C40b) with
GCC 7.3.0 from homebrew with -DTRY=0 and -DTRY=1.