The configure script that comes with doas does not understand
`--disable-shared`, which nixpkgs sometimes adds to
`configureFlags`.
Previously, doas included a patch that would cause its configure
script to ignore this flag instead of rejecting it. This commit
drops that patch and instead uses
`dontAddStaticConfigureFlags=false` (introduced in
b0b5ef7286) to prevent nixpkgs addingn
`--disable-shared` to doas' configureFlags.
e2c555799c