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Good news. I managed to compile and run the old Sprouts wallet using QT Creator on a Mac. Now I can make changes if I want.
Sweet! This means that you got past the errors and warnings. Make a copy, and mess with it as much as you want.
I haven't used qt creator, but I am going to guess that it should let you cross compile a version for the Mac, linux, and windows.
I got past the errors but there are still warnings such as implicit conversions, zero as null pointers repeating over and over (1020 all together).