Ultimately all static strings should be qstr. This entry in the type structure is only used for printing error messages (to tell the type of the bad argument), and printing objects that don't supply a .print method.
f2d and d2f functions from libgcc does not work correctly, most likely due to the ABI being incorrect. libgcc disabled for now.
Can now have null bytes in strings. Can define ROM qstrs per port using qstrdefsport.h
