fix crypto overlay so that it can be imported after haskell.nix

 as it should.

 This is done by adding proper support for musl to libsecp256k1 buid,
 so that we don't rely on haskell.nix overrideAttrs for this.

overlays/crypto/default.nix

@@ -10,15 +10,18 @@ inputs: final: prev: rec {
   libblst = final.callPackage ./libblst.nix { inherit inputs; };
   libsecp256k1 = final.callPackage ./libsecp256k1.nix { inherit inputs; };
 
-  # override the nixpkgs ones which do not have the `lib` prefix.
-  secp256k1 = libsecp256k1;
+  # XXX: deprecated: override the nixpkgs ones which do not have the `lib` prefix.
+  secp256k1 = builtins.trace "WARNING: overriding nixpkgs' secp256k1 with iohk-nix libsecp256k1. This override will go away in July 2023, please use libsecp256k1 directly."
+    libsecp256k1;
 }
 # Make these libraries also available to haskell-nix's pkg-config
 # map when solving for dependencies with cabal.
 // prev.lib.optionalAttrs (prev ? haskell-nix) {
   haskell-nix = prev.haskell-nix // {
     extraPkgconfigMappings = prev.haskell-nix.extraPkgconfigMappings // {
       "libblst" = [ "libblst" ];
+      # switch haskell.nix default mapping from `secp256k1` to our `libsecp256k1`.
+      "libsecp256k1" = ["libsecp256k1"];
       # map libsoidum to our libsodium-vrf, if you include the iohk-nix
       # crypto overlay, you _do_ want the custom libsoidum.
       "libsodium" = [ "libsodium-vrf" ];

overlays/crypto/libsecp256k1.nix

@@ -11,6 +11,8 @@ stdenv.mkDerivation rec {
   configureFlags = [
     "--enable-benchmark=no"
     "--enable-module-recovery"
+  ] ++ lib.optional stdenv.hostPlatform.isMusl [
+    "--enable-static"
   ];
 
   doCheck = true;
@@ -27,4 +29,4 @@ stdenv.mkDerivation rec {
     maintainers = with maintainers; [ ];
     platforms = with platforms; all;
   };
-}
+}