mikmod: fix startup crash on _FORTIFY_SOURCE=3

Without the change `mikmod` crashes at startup as:

    $ nix run nixpkgs#mikmod
    *** buffer overflow detected ***: terminated
    Aborted (core dumped)

The change fixes `snprintf()` buffer size accounting by picking patch
proposed for upstream inclusion:

    https://sourceforge.net/p/mikmod/patches/17/

pkgs/applications/audio/mikmod/default.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchurl, libmikmod, ncurses }:
+{ lib, stdenv, fetchurl, fetchpatch, libmikmod, ncurses }:
 
 stdenv.mkDerivation rec {
   pname = "mikmod";
@@ -9,6 +9,17 @@ stdenv.mkDerivation rec {
     sha256 = "1k54p8pn3jinha0f2i23ad15pf1pamibzcxjrbzjbklpcz1ipc6v";
   };
 
+  patches = [
+    # Fix player startup crash due to stack overflow check:
+    #   https://sourceforge.net/p/mikmod/patches/17/
+    (fetchpatch {
+      name = "fortify-source-3.patch";
+      url = "https://sourceforge.net/p/mikmod/patches/17/attachment/0001-mikmod-fix-startup-crash-on-_FROTIFY_SOURCE-3-system.patch";
+      stripLen = 1;
+      hash = "sha256-YtbnLTsW3oYPo4r3fh3DUd3DD5ogWrCNlrDcneY03U0=";
+    })
+  ];
+
   buildInputs = [ libmikmod ncurses ];
 
   meta = {