Change serf.rb to correct the installation.

packages/serf.rb

@@ -3,7 +3,7 @@ require 'package'
 class Serf < Package
   description 'The serf library is a high performance C-based HTTP client library built upon the Apache Portable Runtime (APR) library.'
   homepage 'https://serf.apache.org/'
-  version '1.3.9-1'
+  version '1.3.9-2'
   source_url 'https://www.apache.org/dist/serf/serf-1.3.9.tar.bz2'
   source_sha256 '549c2d21c577a8a9c0450facb5cca809f26591f048e466552240947bdf7a87cc'
 
@@ -11,8 +11,11 @@ class Serf < Package
   depends_on 'aprutil'
   depends_on 'openssl'
 
+  def self.build
+    system "scons APR=/usr/local APU=/usr/local OPENSSL=/usr/local/include/openssl PREFIX=#{CREW_PREFIX} LIBDIR=#{CREW_LIB_PREFIX}"
+  end
+
   def self.install
-    system "mkdir -p #{CREW_DEST_DIR}/usr/local"
-    system "scons APR=/usr/local APU=/usr/local OPENSSL=/usr/local/include/openssl PREFIX=#{CREW_DEST_DIR}/usr/local install"
+    system "scons install --install-sandbox=#{CREW_DEST_DIR}"
   end
 end