```ruby
require 'formula'

class Nspr <Formula
  @url='https://ftp.mozilla.org/pub/mozilla.org/nspr/releases/v4.7.6/src/nspr-4.7.6.tar.gz'
  @homepage='http://www.mozilla.org/projects/nspr/'
  @md5='c78384602b4b466081a55025446641db'

  def install
    ENV.deparallelize
    Dir.chdir "mozilla/nsprpub" do
      inreplace "pr/src/Makefile.in", "-framework CoreServices -framework CoreFoundation", ""
      system "./configure", "--prefix=#{prefix}",
                            "--disable-debug",
                            "--enable-strip",
                            "--enable-optimize",
                            "--enable-64bit"
      inreplace "config/autoconf.mk", "-install_name @executable_path/$@ ", ""
      system "make"
      system "make install"
    end
  end
end
```

Enable 64 bits on 64 bit machines only
user
```ruby
require 'formula'

class Nspr <Formula
  @url='https://ftp.mozilla.org/pub/mozilla.org/nspr/releases/v4.7.6/src/nspr-4.7.6.tar.gz'
  @homepage='http://www.mozilla.org/projects/nspr/'
  @md5='c78384602b4b466081a55025446641db'

  def install
    require 'hardware'

    ENV.deparallelize
    Dir.chdir "mozilla/nsprpub" do
      inreplace "pr/src/Makefile.in", "-framework CoreServices -framework CoreFoundation", ""

      conf = %W[--prefix=#{prefix} --disable-debug --enable-strip --enable-optimize]
      conf << "--enable-64bit" if Hardware.is_64_bit? and MACOS_VERSION >= 10.6
      system "./configure", *conf

      inreplace "config/autoconf.mk", "-install_name @executable_path/$@ ", ""

      system "make"
      system "make install"
    end
  end
end
```
assistant