isl_0_27: init at 0.27 (#440585)

pkgs/development/libraries/isl/0.27.0.nix

···
+import ./generic.nix rec {
+  version = "0.27";
+  urls = [
+    "mirror://sourceforge/libisl/isl-${version}.tar.xz"
+    "https://libisl.sourceforge.io/isl-${version}.tar.xz"
+  ];
+  sha256 = "sha256-bYurtZ57Zy6Mt4cOh08/e4E7bgDmrz+LBPdXmWVkPVw=";
+  configureFlags = [
+    "--with-gcc-arch=generic" # don't guess -march=/mtune=
+  ];
+}

pkgs/top-level/all-packages.nix

···
       isl_0_20 = callPackage ../development/libraries/isl/0.20.0.nix { };
       isl_0_23 = callPackage ../development/libraries/isl/0.23.0.nix { };
       isl_0_24 = callPackage ../development/libraries/isl/0.24.0.nix { };
+      isl_0_27 = callPackage ../development/libraries/isl/0.27.0.nix { };
     })
     isl
     isl_0_20
     isl_0_23
     isl_0_24
+    isl_0_27
     ;
 
   jackett = callPackage ../servers/jackett { };