Add PCRE is dependency for nginx.

packages/pcre.rb

+require 'package'
+
+class Pcre < Package
+  version '8.39'
+  source_url 'https://dl.dropboxusercontent.com/u/14799278/crew/pcre-8.39.tar.gz' # software source tarball url
+  source_sha1 'b3aec1f643d9701841e2f9d57ac121a7ff448fc8'                  # source tarball sha1 sum
+  
+  def self.build                                                  # self.build contains commands needed to build the software from source
+    system "./configure"
+    system "make"                                                 # ordered chronologically
+  end
+
+  def self.install                                                # self.install contains commands needed to install the software on the target system
+    system "make", "DESTDIR=#{CREW_DEST_DIR}", "install"          # remember to include DESTDIR set to CREW_DEST_DIR - needed to keep track of changes made to system
+  end
+end