netcat: fix build/test on arm64 linux

Author: alebcay

Formula/n/netcat.rb

@@ -27,6 +27,15 @@ class Netcat < Formula
   depends_on "autoconf" => :build
   depends_on "automake" => :build
 
+  # Fix running on Linux ARM64, using patch from Arch Linux ARM.
+  # https://sourceforge.net/p/netcat/bugs/51/
+  patch do
+    on_arm do
+      url "https://raw.githubusercontent.com/archlinuxarm/PKGBUILDs/05ebc1439262e7622ba4ab0c15c2a3bad1ac64c4/extra/gnu-netcat/gnu-netcat-flagcount.patch"
+      sha256 "63ffd690c586b164ec2f80723f5bcc46d009ffd5e0dd78bbe56fd1b770fd0788"
+    end
+  end
+
   def install
     # Regenerate configure script for arm64/Apple Silicon support.
     system "autoreconf", "--force", "--install", "--verbose"