Stop treat warnings as errors. The problem is not in nginx itself but

nginx-push-stream-module still it prevents from compiling nginx.

/reviewed-on !573

component/nginx/buildout.cfg

@@ -98,7 +98,7 @@ configure-options=
   --with-http_v2_module
   --with-http_gzip_static_module
   --with-ld-opt="-L ${zlib:location}/lib -L ${openssl-1.0:location}/lib -L ${pcre:location}/lib  -Wl,-rpath=${pcre:location}/lib -Wl,-rpath=${zlib:location}/lib -Wl,-rpath=${openssl-1.0:location}/lib"
-  --with-cc-opt="-I ${pcre:location}/include -I ${openssl-1.0:location}/include -I ${zlib:location}/include"
+  --with-cc-opt="-I ${pcre:location}/include -I ${openssl-1.0:location}/include -I ${zlib:location}/include -Wno-error"
   --add-module=${nginx-push-stream-module:location}
 
 [nginx-push-stream-output]