bwidget: 1.9.10 -> 1.9.12

Semi-automatic update. These checks were done:

- built on NixOS
- Warning: no binary found that responded to help or version flags. (This warning appears even if the package isn't expected to have binaries.)
- found 1.9.12 with grep in /nix/store/5rrcmy0g4sj5q2yhxxyczgddnjhgjfxm-bwidget-1.9.12
- found 1.9.12 in filename of file in /nix/store/5rrcmy0g4sj5q2yhxxyczgddnjhgjfxm-bwidget-1.9.12