Add pkgconfig support to blst

  buildPhase = ''

    runHook preBuild

    ./build.sh

    ./build.sh ${lib.optionalString stdenv.targetPlatform.isWindows "flavour=mingw64"}

    ./build.sh -shared ${lib.optionalString stdenv.targetPlatform.isWindows "flavour=mingw64"}

    runHook postBuild

  '';

  installPhase = ''

    runHook preInstall

    mkdir -p $out/lib

    cp ./libblst.a $out/lib/

    mkdir -p $out/{lib,include}

    for lib in libblst.{a,so,dylib}; do

      if [ -f $lib ]; then

        cp $lib $out/lib/

      fi

    done

    cp bindings/{blst.h,blst_aux.h} $out/include

    for lib in blst.dll; do

      if [ -f $lib ]; then

        mkdir -p $out/bin

        cp $lib $out/bin/

      fi

    done

    mkdir -p $out/lib/pkgconfig

    cat <<EOF > $out/lib/pkgconfig/libblst.pc

    prefix=$out

    exec_prefix=''\\''${prefix}

    libdir=''\\''${exec_prefix}/lib

    includedir=''\\''${prefix}/include

    Name: libblst

    Description: ${finalAttrs.meta.description}

    URL: ${finalAttrs.meta.homepage}

    Version: ${finalAttrs.version}

    Cflags: -I''\\''${includedir}

    Libs: -L''\\''${libdir} -lblst

    Libs.private:

    EOF

    runHook postInstall

  '';

  # ensure we have the right install id set.  Otherwise the library

  # wouldn't be found during install.  The alternative would be to work

  # lib.optional stdenv.isDarwin "LDFLAGS=-Wl,-install_name,$(out)/lib/libblst.dylib";

  # into the setup.sh

  postFixup = lib.optionalString stdenv.isDarwin ''

    install_name_tool -id $out/lib/libblst.dylib $out/lib/libblst.dylib

  '';

  doCheck = true;

  meta = with lib; {