pngquant 1.7.2

Closes Homebrew/homebrew#13943.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/pngquant.rb

@@ -0,0 +1,22 @@
+require 'formula'
+
+class Pngquant < Formula
+  homepage 'http://pngquant.org/'
+  url 'https://github.com/pornel/improved-pngquant/tarball/1.7.2'
+  sha1 'fcb10d23380824451371f47a62428ce496f21636'
+
+  head 'https://github.com/pornel/improved-pngquant.git'
+
+  depends_on :libpng
+
+  def install
+    ENV.append_to_cflags "-DNDEBUG" # Turn off debug
+    system "make", "PREFIX=#{prefix}", "CC=#{ENV.cc}"
+    bin.install 'pngquant'
+    man1.install 'pngquant.1'
+  end
+
+  def test
+    system "#{bin}/pngquant", "--help"
+  end
+end