I'd guess that it's due to a recursive dependency on ncurses.
bash depends on readline, which was recompiled against ncursesw - spacefm probably has a direct dependency on ncurses, rather than via bash/readline.
If the above is correct, it would be good if you could recompile against ncursesw and also include adwaita-icon-theme as a dep rather than the depreciated gnome-icon-theme.