Patch to compile ruby 1.8.7-p374 on CentOS 6.5 (ruby-install -p 'https://gist.github.com/MicahElliott/8908123/raw/e87d4d553dac05da02a186263e0a7bb69d24ff39/ruby-ossl_pkey_ec.c.diff.diff' ruby 1.8.7)

## ruby-ossl_pkey_ec.c.diff
--- ruby-1.8.7-p374/ext/openssl/ossl_pkey_ec.c	2010-06-21 05:18:59.000000000 -0400
+++ ruby-1.8.7-p374/ext/openssl/ossl_pkey_ec.c.new	2014-02-09 19:21:24.635060547 -0500
@@ -757,8 +757,10 @@
                 method = EC_GFp_mont_method();
             } else if (id == s_GFp_nist) {
                 method = EC_GFp_nist_method();
+#if !defined(OPENSSL_NO_EC2M)
             } else if (id == s_GF2m_simple) {
                 method = EC_GF2m_simple_method();
+#endif
             }

             if (method) {
@@ -811,8 +813,10 @@

             if (id == s_GFp) {
                 new_curve = EC_GROUP_new_curve_GFp;
+#if !defined(OPENSSL_NO_EC2M)
             } else if (id == s_GF2m) {
                 new_curve = EC_GROUP_new_curve_GF2m;
+#endif
             } else {
                 rb_raise(rb_eArgError, "unknown symbol, must be :GFp or :GF2m");
             }