Add libspng package (#3434)

* Add libspng package

* Remove deps that are included in the base install of crew.

packages/libspng.rb

+require 'package'
+
+class Libspng < Package
+  description 'libspng is a C library for reading and writing Portable Network Graphics (PNG) format files with a focus on security and ease of use.'
+  homepage 'https://libspng.org'
+  version '0.5.0'
+  source_url 'https://gitlab.com/randy408/libspng/uploads/3d980bac86c51368f40af2f1ac79a057/libspng-0.5.0.tar.xz'
+  source_sha256 '220a653802559943ae43fd48f03ba6ff3935a5243766d9ee5ff905240d4399a7'
+
+  binary_url ({
+  })
+  binary_sha256 ({
+  })
+
+  def self.build
+    Dir.mkdir 'build'
+    Dir.chdir('build') do
+      system "cmake -DCMAKE_INSTALL_PREFIX=#{CREW_PREFIX} .."
+      system "sed -i 's,build\/tests\/libspng\.pc,build\/libspng.pc,' cmake_install.cmake"
+      system 'make'
+    end
+  end
+
+  def self.install
+    Dir.chdir('build') do
+      system 'make', "DESTDIR=#{CREW_DEST_DIR}", 'install'
+    end
+  end
+end