This commit adds required files into the offload build closure,
which means adding RT_API_ATTRS and other markers.
The implementation does not work for CUDA yet, because of
std::variant,swap,reverse usage. These issues will be resolved
separately (e.g. by using libcudacxx header files).
Address review comments
Integer output data editing (I,B,O,Z)
Full integer output formatting
Stub out some work in progress
Progress on E output data editing
E, D, EN, and ES output editing done
Fw.d output editing
Real G output editing
G output editing for reals
Make environment a distinct module
CHARACTER and LOGICAL output editing
Minimal decimal representations for E0, F0, G0 editing
Move real output editing code into its own file
Fix/dodge some GCC build problems
Prep work for external I/O statement state
External HELLO, WORLD
Fix build problem with GCC
Add virtual destructors where needed
Add new test
Original-commit: flang-compiler/f18@c3f1774f8e
Reviewed-on: https://github.com/flang-compiler/f18/pull/950
