icon: Init at 9.5.1

Icon is a very high level general-purpose programming language with
extensive features for processing strings (text) and data structures.

Closes #16036.

pkgs/development/interpreters/icon-lang/default.nix

···
+{ stdenv, fetchFromGitHub, libX11, libXt }:
+
+stdenv.mkDerivation rec {
+  name = "icon-lang-${version}";
+  version = "9.5.1";
+  src = fetchFromGitHub {
+    rev = "39d7438e8d23ccfe20c0af8bbbf61e34d9c715e9";
+    owner = "gtownsend";
+    repo = "icon";
+    sha256 = "1gkvj678ldlr1m5kjhx6zpmq11nls8kxa7pyy64whgakfzrypynw";
+  };
+  buildInputs = [ libX11 libXt ];
+
+  configurePhase = ''
+    make X-Configure name=linux
+  '';
+
+  installPhase = ''
+    make Install dest=$out
+  '';
+
+  meta = with stdenv.lib; {
+    description = ''A very high level general-purpose programming language'';
+    maintainers = with maintainers; [ vrthra ];
+    platforms = platforms.linux;
+    license = licenses.publicDomain;
+    homepage = https://www.cs.arizona.edu/icon/;
+  };
+}

pkgs/top-level/all-packages.nix

···
 
   gio-sharp = callPackage ../development/libraries/gio-sharp { };
 
+  icon-lang = callPackage ../development/interpreters/icon-lang { };
+
   libgit2 = callPackage ../development/libraries/git2 (
     stdenv.lib.optionalAttrs stdenv.isDarwin {
       inherit (darwin) libiconv;