nginx: enable thread pools by default

The thread pool feature can be enabled without significant extra binary size.  Thread pools can increase performance by an order of magnitude on some configurations

Signed-off-by: Derek Straka <derek@asterius.io>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-webserver/recipes-httpd/nginx/nginx.inc

@@ -71,6 +71,7 @@ do_configure () {
     --http-scgi-temp-path=/run/nginx/scgi_temp \
     --pid-path=/run/nginx/nginx.pid \
     --prefix=${prefix} \
+    --with-threads \
     --with-http_ssl_module \
     --with-http_gzip_static_module \
     ${EXTRA_OECONF} ${PACKAGECONFIG_CONFARGS}