Ioan,
Simply download the .zip from the drexjj/sbitx 64-bit site. The TZ fix is already built in here.
The currently available 64-bit sbitx_gtk.c includes additional cw macro fixes. After unpacking, copy the sbitx_gtk.c file to the sbitx folder, then build it with the ./build sbitx command.?If you haven't done this yet, make a copy of the sbitx folder first. There are many things you can do with File Manager.
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Gyula HA3HZ