Try #1713:

ci.nix

@@ -31,10 +31,12 @@
     # Update supported-ghc-versions.md to reflect any changes made here.
     nixpkgs.lib.optionalAttrs (nixpkgsName == "R2205") {
       ghc865 = false;
+      ghc810420210212 = false; # TODO remove when plutus no longer uses this.
       ghc8107 = false;
     } // nixpkgs.lib.optionalAttrs (nixpkgsName == "unstable") {
       ghc865 = false;
       ghc884 = false; # Native version is used to boot 9.0.1
+      ghc810420210212 = false; # TODO remove when plutus no longer uses this.
       ghc8107 = true;
       ghc902 = false;
       ghc924 = true;
@@ -43,7 +45,7 @@
     nixpkgs.lib.filter (v:
         # We have less x86_64-darwin build capacity so build fewer GhC versions
         (v != "x86_64-darwin" || (
-           !__elem compiler-nix-name ["ghc8104" "ghc810420210212" "ghc8105" "ghc8106" "ghc901" "ghc921" "ghc922"]))
+           !__elem compiler-nix-name ["ghc8104" "ghc8105" "ghc8106" "ghc901" "ghc921" "ghc922"]))
       &&
         # aarch64-darwin requires ghc 8.10.7
         (v != "aarch64-darwin" || (

lib/call-cabal-project-to-nix.nix

@@ -569,6 +569,7 @@ let
           # the `with-compiler:` in the `cabal.project` file.
           ghc.targetPrefix}ghc \
         --with-ghc-pkg=${ghc.targetPrefix}ghc-pkg \
+        --with-pkg-config=${ghc.targetPrefix}pkg-config \
         --enable-tests \
         --enable-benchmarks \
         ${pkgs.lib.optionalString (ghc.targetPrefix == "js-unknown-ghcjs-")

nix-tools/ci.toml

@@ -1,4 +1,4 @@
 [dimensions]
 os = [ "x86_64-darwin", "x86_64-linux" ]
-compiler = [ "ghc865", "ghc882", "ghc883", "ghc884", "ghc8102", "ghc8103", "ghc8104", "ghc8105", "ghc8106", "ghc8107" ]
+compiler = [ "ghc865", "ghc882", "ghc883", "ghc884", "ghc8102", "ghc8103", "ghc8104", "ghc810420210212", "ghc8105", "ghc8106", "ghc8107" ]
 disable = [ ]