defaultCrateOverrides: override crates necessary for building sequoia

See https://git.sr.ht/~erictapen/sequoia for a flake using these
overrides.

pkgs/build-support/rust/default-crate-overrides.nix

@@ -1,6 +1,7 @@
 { stdenv, pkg-config, curl, darwin, libiconv, libgit2, libssh2,
   openssl, sqlite, zlib, dbus, dbus-glib, gdk-pixbuf, cairo, python3,
-  libsodium, postgresql, gmp, foundationdb, ... }:
+  libsodium, postgresql, gmp, foundationdb, capnproto, nettle, clang,
+  llvmPackages, ... }:
 
 let
   inherit (darwin.apple_sdk.frameworks) CoreFoundation Security;
@@ -10,6 +11,10 @@ in
     buildInputs = [ cairo ];
   };
 
+  capnp-rpc = attrs: {
+    nativeBuildInputs = [ capnproto ];
+  };
+
   cargo = attrs: {
     buildInputs = [ openssl zlib curl ]
       ++ stdenv.lib.optionals stdenv.isDarwin [ CoreFoundation Security libiconv ];
@@ -84,6 +89,12 @@ in
     buildInputs = [ dbus ];
   };
 
+  nettle-sys = attrs: {
+    nativeBuildInputs = [ pkg-config ];
+    buildInputs = [ nettle clang ];
+    LIBCLANG_PATH = "${llvmPackages.libclang}/lib";
+  };
+
   openssl = attrs: {
     buildInputs = [ openssl ];
   };
@@ -107,6 +118,36 @@ in
     propagatedBuildInputs = [ Security ];
   };
 
+  sequoia-openpgp = attrs: {
+    buildInputs = [ gmp ];
+  };
+
+  sequoia-openpgp-ffi = attrs: {
+    buildInputs = [ gmp ];
+  };
+
+  sequoia-ipc = attrs: {
+    buildInputs = [ gmp ];
+  };
+
+  sequoia-guide = attrs: {
+    buildInputs = [ gmp ];
+  };
+
+  sequoia-store = attrs: {
+    nativeBuildInputs = [ capnproto ];
+    buildInputs = [ sqlite gmp ];
+  };
+
+  sequoia-sq = attrs: {
+    buildInputs = [ sqlite gmp ];
+  };
+
+  sequoia-tool = attrs: {
+    nativeBuildInputs = [ capnproto ];
+    buildInputs = [ sqlite gmp ];
+  };
+
   serde_derive = attrs: {
     buildInputs = stdenv.lib.optional stdenv.isDarwin Security;
   };