falcon: use gcc10Stdenv

build fails with gcc 11

pkgs/development/interpreters/falcon/default.nix

···
-{ lib, gccStdenv, fetchFromGitHub, cmake, pkg-config, pcre, zlib, sqlite }:
+{ lib, stdenv, fetchFromGitHub, cmake, pkg-config, pcre, zlib, sqlite }:
 
-gccStdenv.mkDerivation {
+stdenv.mkDerivation {
   pname = "falcon";
   version = "unstable-2018-10-23";
 

pkgs/top-level/all-packages.nix

···
 
   hop = callPackage ../development/compilers/hop { };
 
-  falcon = callPackage ../development/interpreters/falcon { };
+  falcon = callPackage ../development/interpreters/falcon {
+    stdenv = gcc10Stdenv;
+  };
 
   fsharp = callPackage ../development/compilers/fsharp { };