icu: Remove redundant compiler overrides

We are not using gcc-7 by default anymore, and later gccs do not have this problem.

pkgs/top-level/all-packages.nix

@@ -17875,65 +17875,40 @@ with pkgs;
 
   icu58 = callPackage (import ../development/libraries/icu/58.nix fetchurl) ({
     nativeBuildRoot = buildPackages.icu58.override { buildRootOnly = true; };
-  } //
+  });
-    (lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
-      stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
   icu59 = callPackage ../development/libraries/icu/59.nix ({
     nativeBuildRoot = buildPackages.icu59.override { buildRootOnly = true; };
-  } // (lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
+  });
-      stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
   icu60 = callPackage ../development/libraries/icu/60.nix ({
     nativeBuildRoot = buildPackages.icu60.override { buildRootOnly = true; };
-  } // (lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
+  });
-      stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
   icu63 = callPackage ../development/libraries/icu/63.nix ({
     nativeBuildRoot = buildPackages.icu63.override { buildRootOnly = true; };
-  } // (lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
+  });
-      stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
   icu64 = callPackage ../development/libraries/icu/64.nix ({
     nativeBuildRoot = buildPackages.icu64.override { buildRootOnly = true; };
-  } // (lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
+  });
-      stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
   icu65 = callPackage ../development/libraries/icu/65.nix ({
     nativeBuildRoot = buildPackages.icu65.override { buildRootOnly = true; };
-  } // (lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
+  });
-      stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
   icu66 = callPackage ../development/libraries/icu/66.nix ({
     nativeBuildRoot = buildPackages.icu66.override { buildRootOnly = true; };
-  } // (lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
+  });
-      stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
-  }));
   icu67 = callPackage ../development/libraries/icu/67.nix ({
     nativeBuildRoot = buildPackages.icu67.override { buildRootOnly = true; };
-  } // (lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
+  });
-      stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
   icu68 = callPackage ../development/libraries/icu/68.nix ({
     nativeBuildRoot = buildPackages.icu68.override { buildRootOnly = true; };
-  } // (lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
+  });
-      stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
   icu69 = callPackage ../development/libraries/icu/69.nix ({
     nativeBuildRoot = buildPackages.icu69.override { buildRootOnly = true; };
-  } // (lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
+  });
-      stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
   icu70 = callPackage ../development/libraries/icu/70.nix ({
     nativeBuildRoot = buildPackages.icu70.override { buildRootOnly = true; };
-  } // (lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
+  });
-      stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
   icu71 = callPackage ../development/libraries/icu/71.nix ({
     nativeBuildRoot = buildPackages.icu71.override { buildRootOnly = true; };
-  } // (lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
+  });
-      stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
 
   icu = icu71;