search winsock libraries explicitly

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62628 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Sync-with-trunk: r62628

Author: nobu

ext/openssl/extconf.rb

@@ -40,6 +40,7 @@
 def find_openssl_library
   if $mswin || $mingw
     # required for static OpenSSL libraries
+    have_library("ws2_32")
     have_library("gdi32") # OpenSSL <= 1.0.2 (for RAND_screen())
     have_library("crypt32")
   end