fairymax: use SRI hash format

pkgs/games/fairymax/default.nix

···
-{lib, stdenv, fetchurl}:
+{ lib
+, stdenv
+, fetchurl
+}:
+
 stdenv.mkDerivation rec {
   pname = "fairymax";
   version = "4.8";
+
   src = fetchurl {
     url = "http://home.hccnet.nl/h.g.muller/fmax4_8w.c";
-    sha256 = "01vxhpa4z0613mkgkzmsln293wxmyp5kdzil93cd1ik51q4gwjca";
+    hash = "sha256-ikn+CA5lxtDYSDT+Nsv1tfORhKW6/vlmHcGAT9SFfQc=";
   };
+
   ini = fetchurl {
     url = "http://home.hccnet.nl/h.g.muller/fmax.ini";
-    sha256 = "1zwx70g3gspbqx1zf9gm1may8jrli9idalvskxbdg33qgjys47cn";
+    hash = "sha256-lh2ivXx4jNdWn3pT1WKKNEvkVQ31JfdDx+vqNx44nf8=";
   };
+
   unpackPhase = ''
     cp ${src} fairymax.c
     cp ${ini} fmax.ini
   '';
+
   buildPhase = ''
-    $CC *.c -Wno-return-type -o fairymax -DINI_FILE='"'"$out/share/fairymax/fmax.ini"'"'
+    cc *.c -Wno-return-type \
+      -o fairymax \
+      -DINI_FILE='"'"$out/share/fairymax/fmax.ini"'"'
   '';
+
   installPhase = ''
     mkdir -p "$out"/{bin,share/fairymax}
     cp fairymax "$out/bin"
     cp fmax.ini "$out/share/fairymax"
   '';
-  meta = {
+
+  meta = with lib; {
+    homepage = "http://home.hccnet.nl/h.g.muller/dwnldpage.html";
     description = "A small chess engine supporting fairy pieces";
     longDescription = ''
-       A version of micro-Max that reads the piece description
-       from a file fmax.ini, so that arbitrary fairy pieces can be
-       implemented. This version (4.8J) supports up to 15 piece types,
-       and board sizes up to 12x8. A Linux port exists in the
-       format of a debian package.
+       A version of micro-Max that reads the piece description from a file
+       fmax.ini, so that arbitrary fairy pieces can be implemented. This version
+       (4.8J) supports up to 15 piece types, and board sizes up to 12x8.
     '';
-    license = lib.licenses.free ;
-    maintainers = [lib.maintainers.raskin];
-    platforms = lib.platforms.all;
-    homepage = "http://home.hccnet.nl/h.g.muller/dwnldpage.html";
+    license = licenses.free;
+    maintainers = [ maintainers.raskin ];
+    platforms = platforms.all;
   };
 }