xcur2png: fix cross-build (#343074)

pkgs/tools/graphics/xcur2png/default.nix

@@ -1,4 +1,12 @@
-{ lib, stdenv, fetchFromGitHub, pkg-config, libpng, xorg }:
+{
+  lib,
+  stdenv,
+  fetchFromGitHub,
+  fetchpatch,
+  pkg-config,
+  libpng,
+  xorg,
+}:
 
 stdenv.mkDerivation rec {
   pname = "xcur2png";
@@ -11,6 +19,17 @@ stdenv.mkDerivation rec {
     sha256 = "0858wn2p14bxpv9lvaz2bz1rk6zk0g8zgxf8iy595m8fqv4q2fya";
   };
 
+  patches = [
+    # https://github.com/eworm-de/xcur2png/pull/3
+    ./malloc.diff
+
+    # fix byte overflows due to off-by-one error
+    (fetchpatch {
+      url = "https://github.com/eworm-de/xcur2png/commit/aa035462d950fab35d322cb87fd2f0d702251e82.patch";
+      hash = "sha256-hlmJ/bcDSl1ADs0jp+JrAgAaMzielUSRVPad+plnSZg=";
+    })
+  ];
+
   nativeBuildInputs = [
     pkg-config
   ];

pkgs/tools/graphics/xcur2png/malloc.diff

@@ -0,0 +1,33 @@
+--- a/xcur2png.c
++++ b/xcur2png.c
+@@ -16,7 +16,10 @@
+ /* Todo: atoi error handling */
+ /* help is -h in manual */
+
++#if HAVE_CONFIG_H
+ #include <config.h>
++#endif
++#undef malloc
+
+ #define _ATFILE_SOURCE
+ #include <stdio.h>
+@@ -34,6 +37,19 @@
+ #include <png.h>
+ #include <X11/Xcursor/Xcursor.h>
+
++
++void *malloc ();
++
++/* Allocate an N-byte block of memory from the heap.
++   If N is zero, allocate a 1-byte block.  */
++
++void* rpl_malloc (size_t n)
++{
++  if (n == 0)
++    n = 1;
++  return malloc (n);
++}
++
+ #define PNG_SETJMP_NOT_SUPPORTED 1
+ 
+ #define PROGRESS_SHARPS 50 /* total number of progress sharps */