libzt 1.3.1 (new formula)

Closes #39552.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Formula/libzt.rb

@@ -0,0 +1,30 @@
+class Libzt < Formula
+  desc "Encrypted P2P networking library for applications (GPLv3)"
+  homepage "https://www.zerotier.com"
+
+  url "https://github.com/zerotier/libzt.git",
+    :tag      => "1.3.1-hb1",
+    :revision => "d5b064623e1161196fd5bc14668e83bec2c27717"
+
+  depends_on "cmake" => :build
+
+  def install
+    system "cmake", ".", *std_cmake_args
+    system "cmake", "--build", "."
+    system "make", "install"
+    prefix.install "LICENSE.GPL-3" => "LICENSE"
+  end
+
+  test do
+    (testpath/"test.cpp").write <<~EOS
+      #include <cstdlib>
+      #include <ZeroTier.h>
+      int main()
+      {
+        return zts_socket(0,0,0) != -2;
+      }
+    EOS
+    system ENV.cxx, "-v", "test.cpp", "-o", "test", "-L#{lib}", "-lzt"
+    system "./test"
+  end
+end