diff --git a/ext/puma_http11/extconf.rb b/ext/puma_http11/extconf.rb
index 1778c3ff..e523abaa 100644
--- a/ext/puma_http11/extconf.rb
+++ b/ext/puma_http11/extconf.rb
@@ -2,7 +2,8 @@ require 'mkmf'
 
 dir_config("puma_http11")
 
-$defs.push "-Wno-deprecated-declarations"
-$libs += " -lssl -lcrypto "
+if %w'ssl ssleay32'.find {|ssl| have_library(ssl, 'SSL_CTX_new')} and
+  %w'crypto libeay32'.find {|crypto| have_library(crypto, 'BIO_read')}
 
-create_makefile("puma/puma_http11")
+  create_makefile("puma/puma_http11")
+end