HelloCoroutine on Platformio on Digispark (Attiny85) fails compile

[mkarliner]

I've tried compiling the HelloCoroutine code on Platformio for the Digispark board, which is attiny85 based.
I get the following compile errors

Demo repo is here: git@github.com:mkarliner/AceTest.git

In file included from .pio/libdeps/digispark-tiny/AceCommon/src/AceCommon.h:55:0,
                 from .pio/libdeps/digispark-tiny/AceRoutine/src/ace_routine/Coroutine.h:30,
                 from .pio/libdeps/digispark-tiny/AceRoutine/src/AceRoutine.h:49,
                 from src/main.cpp:8:
.pio/libdeps/digispark-tiny/AceCommon/src/print_str/PrintStr.h:130:10: error: 'void ace_common::PrintStrBase::flush()' marked 'override', but does not override
     void flush() override {
          ^~~~~
Compiling .pio/build/digispark-tiny/libfea/AceRoutine/ace_routine/Coroutine.cpp.o
*** [.pio/build/digispark-tiny/src/main.cpp.o] Error 1
In file included from .pio/libdeps/digispark-tiny/AceCommon/src/AceCommon.h:55:0,
                 from .pio/libdeps/digispark-tiny/AceRoutine/src/ace_routine/Coroutine.h:30,
                 from .pio/libdeps/digispark-tiny/AceRoutine/src/ace_routine/Coroutine.cpp:25:
.pio/libdeps/digispark-tiny/AceCommon/src/print_str/PrintStr.h:130:10: error: 'void ace_common::PrintStrBase::flush()' marked 'override', but does not override
     void flush() override {
          ^~~~~
*** [.pio/build/digispark-tiny/libfea/AceRoutine/ace_routine/Coroutine.cpp.o] Error 1

[bxparks]

I don't support PlatformIO so you have to work a little harder. If you trace the code into AceCommon, you'll see that there are a bunch of #ifdef macros for the ATtiny85. Apparently PlatformIO does not define those macros. If you find out what those macros are, perhaps you can submit a PR to the AceCommon project, just like this one which solves a very similar problem: bxparks/AceCommon#28

[Converting this into a Discussion, because it's a bug with AceRoutine.]