Add :build to libtasn1.rb dependencies

packages/libtasn1.rb

@@ -5,6 +5,12 @@ class Libtasn1 < Package
   source_url 'http://ftpmirror.gnu.org/libtasn1/libtasn1-4.10.tar.gz'
   source_sha1 'c7b36fa50866bbc889f7503c7fd1e9f9d7c52a64'
 
+  # bison, diff, cmp are required at compile-time
+  depends_on 'buildessential' => :build
+  depends_on 'pkgconfig' => :build
+  depends_on 'bison' => :build
+  depends_on 'diffutils' => :build
+
   def self.build
     system "./configure", "--enable-shared", "--disable-static", "--with-pic", "--prefix=/usr/local"
     system "make"