openssl: Detect the availability of RAND_egd (tiny change)

Alternatives like LibreSSL don't provide RAND_egd() anymore.
Fixes compilation on OpenBSD.

configure.ac

@@ -392,6 +392,7 @@ AS_IF([test x"$with_ssl" = xopenssl], [
         AC_MSG_NOTICE([compiling in support for SSL via OpenSSL])
         AC_LIBOBJ([openssl])
         LIBS="$LIBSSL $LIBS"
+        AC_CHECK_FUNCS([RAND_egd])
       elif test x"$with_ssl" != x
       then
         AC_MSG_ERROR([--with-ssl=openssl was given, but SSL is not available.])

src/openssl.c

@@ -91,9 +91,11 @@ init_prng (void)
   if (RAND_status ())
     return;
 
+#ifdef HAVE_RAND_EGD
   /* Get random data from EGD if opt.egd_file was used.  */
   if (opt.egd_file && *opt.egd_file)
     RAND_egd (opt.egd_file);
+#endif
 
   if (RAND_status ())
     return;