diff --git a/ext/memcached/extconf.rb b/ext/memcached/extconf.rb
index 807caf01..f6c15edd 100644
--- a/ext/memcached/extconf.rb
+++ b/ext/memcached/extconf.rb
@@ -5,50 +5,54 @@
   abort 'Please install SASL to continue. The package is called libsasl2-dev on Ubuntu and cyrus-sasl on Gentoo.'
 end
 
-HERE = File.expand_path(File.dirname(__FILE__))
-LIBMEMCACHED_DIR = Dir.glob(File.join(HERE, '..', '..', 'vendor','libmemcached-1.0.18')).first
+HERE = __dir__
+LIBMEMCACHED_DIR = Dir.glob(File.join(HERE, '..', '..', 'vendor', 'libmemcached-1.0.18')).first
 
-SOLARIS_32 = RbConfig::CONFIG['target'] == "i386-pc-solaris2.10"
+SOLARIS_32 = RbConfig::CONFIG['target'] == 'i386-pc-solaris2.10'
 BSD = RbConfig::CONFIG['host_os'].downcase =~ /bsd/
 
-$CFLAGS = "#{RbConfig::CONFIG['CFLAGS']} #{$CFLAGS}".gsub("$(cflags)", "").gsub("-fno-common", "").gsub("-Wdeclaration-after-statement", "")
-$CFLAGS << " -Os"
-$CFLAGS << " -std=gnu99" if SOLARIS_32
-$CFLAGS << " -I/usr/local/include" if BSD
-$EXTRA_CONF = " --disable-64bit" if SOLARIS_32
-$LDFLAGS = "#{RbConfig::CONFIG['LDFLAGS']} #{$LDFLAGS} -L#{RbConfig::CONFIG['libdir']}".gsub("$(ldflags)", "").gsub("-fno-common", "")
+$CFLAGS = "#{RbConfig::CONFIG['CFLAGS']} #{$CFLAGS}".gsub('$(cflags)', '').gsub('-fno-common', '').gsub(
+  '-Wdeclaration-after-statement', ''
+)
+$CFLAGS << ' -Os'
+$CFLAGS << ' -std=gnu99' if SOLARIS_32
+$CFLAGS << ' -I/usr/local/include' if BSD
+$EXTRA_CONF = ' --disable-64bit' if SOLARIS_32
+$LDFLAGS = "#{RbConfig::CONFIG['LDFLAGS']} #{$LDFLAGS} -L#{RbConfig::CONFIG['libdir']}".gsub('$(ldflags)', '').gsub(
+  '-fno-common', ''
+)
 $CXXFLAGS = "#{RbConfig::CONFIG['CXXFLAGS']} -fPIC"
-$CC = "CC=#{RbConfig::MAKEFILE_CONFIG["CC"].inspect}"
+$CC = "CC=#{RbConfig::MAKEFILE_CONFIG['CC'].inspect}"
 
 # JRuby's default configure options can't build libmemcached properly
-LIBM_CFLAGS = defined?(JRUBY_VERSION) ? "-fPIC -g -O2" : $CFLAGS
-LIBM_LDFLAGS = defined?(JRUBY_VERSION) ? "-fPIC -lsasl2 -lm" : $LDFLAGS
+LIBM_CFLAGS = defined?(JRUBY_VERSION) ? '-fPIC -g -O2' : $CFLAGS
+LIBM_LDFLAGS = defined?(JRUBY_VERSION) ? '-fPIC -lsasl2 -lm' : $LDFLAGS
 
-GMAKE_CMD = RbConfig::CONFIG['host_os'].downcase =~ /bsd|solaris/ ? "gmake" : "make"
+GMAKE_CMD = RbConfig::CONFIG['host_os'].downcase =~ /bsd|solaris/ ? 'gmake' : 'make'
 
 if ENV['DEBUG']
-  puts "Setting debug flags."
-  $CFLAGS << " -O0 -ggdb -DHAVE_DEBUG"
-  $EXTRA_CONF = ""
+  puts 'Setting debug flags.'
+  $CFLAGS << ' -O0 -ggdb -DHAVE_DEBUG'
+  $EXTRA_CONF = ''
 end
 
 def compile_libmemcached
-  return if ENV["EXTERNAL_LIB"]
+  return if ENV['EXTERNAL_LIB']
 
   Dir.chdir(LIBMEMCACHED_DIR) do
-    Dir.mkdir("build") if !Dir.exists?("build")
-    build_folder = File.join(LIBMEMCACHED_DIR, "build")
+    Dir.mkdir('build') unless Dir.exist?('build')
+    build_folder = File.join(LIBMEMCACHED_DIR, 'build')
 
-    ts_now=(Time.now - 1800).strftime("%Y%m%d%H%M.%S")
+    ts_now = (Time.now - 1800).strftime('%Y%m%d%H%M.%S')
     run("find . | xargs touch -t #{ts_now}", "Touching all files so autoconf doesn't run.")
     run("env CFLAGS='-fPIC #{LIBM_CFLAGS}' LDFLAGS='-fPIC #{LIBM_LDFLAGS}' ./configure --prefix=#{build_folder} --libdir=#{build_folder}/lib --with-pic --without-memcached --disable-shared --disable-util\
-s --disable-dependency-tracking #{$CC} #{$EXTRA_CONF} 2>&1", "Configuring libmemcached.")
+s --disable-dependency-tracking #{$CC} #{$EXTRA_CONF} 2>&1", 'Configuring libmemcached.')
     run("#{GMAKE_CMD} clean 2>&1")
     run("#{GMAKE_CMD} CXXFLAGS='#{$CXXFLAGS}' 2>&1")
     run("#{GMAKE_CMD} install 2>&1")
 
-    pcfile = File.join(LIBMEMCACHED_DIR, "build", "lib", "pkgconfig", "libmemcached.pc")
-    $LDFLAGS << " -lsasl2 " + `pkg-config --libs --static #{pcfile}`.strip
+    pcfile = File.join(LIBMEMCACHED_DIR, 'build', 'lib', 'pkgconfig', 'libmemcached.pc')
+    $LDFLAGS << ' -lsasl2 ' + `pkg-config --libs --static #{pcfile}`.strip
   end
   $DEFLIBPATH.unshift("#{LIBMEMCACHED_DIR}/build")
   dir_config('memcached', "#{LIBMEMCACHED_DIR}/build/include", "#{LIBMEMCACHED_DIR}/build/lib")
@@ -62,10 +66,8 @@ def run(cmd, reason = nil)
 
 compile_libmemcached
 
-$libs = append_library($libs, "stdc++")
+$libs = append_library($libs, 'stdc++')
 
-unless have_library 'memcached' and have_header 'libmemcached/memcached.h'
-  abort "ERROR: Failed to build libmemcached"
-end
+abort 'ERROR: Failed to build libmemcached' unless have_library 'memcached' and have_header 'libmemcached/memcached.h'
 
 create_makefile 'memcached'