doas: drop patch, use dontAddStaticConfigureFlags instead

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
b0b5ef7) to prevent nixpkgs addingn
`--disable-shared` to doas' configureFlags.

pkgs/tools/security/doas/default.nix

@@ -32,13 +32,11 @@ stdenv.mkDerivation rec {
     # Allow doas to discover binaries in /run/current-system/sw/{s,}bin and
     # /run/wrappers/bin
     ./0001-add-NixOS-specific-dirs-to-safe-PATH.patch
-
-    # Standard environment supports "dontDisableStatic" knob, but has no
-    # equivalent for "--disable-shared", so I have to patch "configure"
-    # script instead.
-    ./disable-shared.patch
   ];
 
+  # ./configure script does not understand `--disable-shared`
+  dontAddStaticConfigureFlags = true;
+
   postPatch = ''
     sed -i '/\(chown\|chmod\)/d' GNUmakefile
   '' + lib.optionalString (withPAM && stdenv.hostPlatform.isStatic) ''