gnupg: correct a typo in their source code

pkgs/tools/security/gnupg/20.nix

@@ -20,6 +20,9 @@ stdenv.mkDerivation rec {
 
   patchPhase = ''
     find tests -type f | xargs sed -e 's@/bin/pwd@${coreutils}&@g' -i
+  '' + stdenv.lib.optionalString stdenv.isDarwin ''
+    find . -name pcsc-wrapper.c | xargs sed -i 's/typedef unsinged int pcsc_dword_t/typedef unsigned int pcsc_dword_t/'
+  '' + ''
     patch gl/stdint_.h < ${./clang.patch}
   '';