Without the fix build on ncurses-6.3 fails as:
src/tools/ui.c: In function 'ui_draw_footer_button':
src/tools/ui.c:329:9: error: format not a string literal and no format arguments [-Werror=format-security]
329 | wprintw(ui->win_footer->win, key);
| ^~~~~~~
While at it pulled fix for upstream gcc-10 and clang-12 which
default to -fno-common. Otherwise build would fail as:
$ nix build --impure --expr 'with import ./. {}; gmu.override { stdenv = clang12Stdenv; }' -L
...
gmu> ld: feloader.o:(.bss+0x8): multiple definition of `dlsymunion';
decloader.o:(.bss+0x8): first defined here
