cppad: migrate from homebrew/science

Closes #17028.

Signed-off-by: FX Coudert <fxcoudert@gmail.com>

Formula/cppad.rb

@@ -0,0 +1,37 @@
+class Cppad < Formula
+  desc "Differentiation of C++ Algorithms"
+  homepage "https://www.coin-or.org/CppAD"
+  url "http://www.coin-or.org/download/source/CppAD/cppad-20170820.epl.tgz"
+  version "20170820"
+  sha256 "f491115fe0be06cc29cac938e90f6e3cfbddb9cb7f0a0ae1f68f17123e32d0c1"
+  head "https://github.com/coin-or/CppAD.git"
+
+  depends_on "cmake" => :build
+
+  def install
+    mkdir "build" do
+      system "cmake", "..", *std_cmake_args,
+                      "-Dcppad_prefix=#{prefix}"
+      system "make", "install"
+    end
+    pkgshare.install "example"
+  end
+
+  test do
+    (testpath/"test.cpp").write <<-EOS
+      #include <cassert>
+      #include <cppad/utility/thread_alloc.hpp>
+
+      int main(void) {
+        extern bool acos(void);
+        bool ok = acos();
+        assert(ok);
+        return static_cast<int>(!ok);
+      }
+    EOS
+
+    system ENV.cxx, "#{pkgshare}/example/general/acos.cpp", "-I#{include}",
+                    "test.cpp", "-o", "test"
+    system "./test"
+  end
+end