gpatch: import homebrew/dupes into core.

Formula/gpatch.rb

@@ -0,0 +1,33 @@
+class Gpatch < Formula
+  desc "Apply a diff file to an original"
+  homepage "https://savannah.gnu.org/projects/patch/"
+  url "https://ftpmirror.gnu.org/patch/patch-2.7.5.tar.xz"
+  mirror "https://ftp.gnu.org/gnu/patch/patch-2.7.5.tar.xz"
+  sha256 "fd95153655d6b95567e623843a0e77b81612d502ecf78a489a4aed7867caa299"
+
+  bottle do
+    cellar :any_skip_relocation
+    rebuild 1
+    sha256 "526112f0034e80e4b830d6a4b486073be6ea79743a1f4cb7b96e7564bf9dbae4" => :el_capitan
+    sha256 "6de31643dafee3863e42bfff45ad8b128bd45fa02ea46a9a98732ad84e8b59ed" => :yosemite
+    sha256 "0eee795f5f3c9d9e33bfcf83a207cea34fa41f4077fe99e0edc3ff894aedad41" => :mavericks
+  end
+
+  def install
+    system "./configure", "--disable-dependency-tracking", "--prefix=#{prefix}"
+    system "make", "install"
+  end
+
+  test do
+    testfile = testpath/"test"
+    testfile.write "homebrew\n"
+    patch = <<-EOS.undent
+      1c1
+      < homebrew
+      ---
+      > hello
+    EOS
+    pipe_output("#{bin}/patch #{testfile}", patch)
+    assert_equal "hello", testfile.read.chomp
+  end
+end