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
b0b5ef7286dca098f40f5075175105c3c0dfbe05) to prevent nixpkgs addingn
`--disable-shared` to doas' configureFlags.

pkgs/tools/security/doas/default.nix

···
     # 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

pkgs/tools/security/doas/disable-shared.patch

···
-Accept and ignore "--disable-shared" option passed by pkgsStatic.stdenv.
-Without this patch, configure phase fails with "unknown option".
-
---- a/configure	1970-01-01 00:00:00.000000000 -0500
-+++ b/configure	1970-01-01 00:00:00.000000000 -0500
-@@ -46,6 +46,7 @@
- 	opt=${x%%=*}
- 	var=${x#*=}
- 	case "$opt" in
-+	--disable-shared) : ;;
- 	--prefix) PREFIX=$var ;;
- 	--exec-prefix) EPREFIX=$var ;;
- 	--bindir) BINDIR=$var ;;