device-observatory: fix compilation with newer libmicrohttpd

API change.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

utils/device-observatory/Makefile

@@ -2,7 +2,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=device-observatory
 PKG_VERSION:=1.2.0
-PKG_RELEASE:=6
+PKG_RELEASE:=7
 
 PKG_SOURCE_URL:=https://codeload.github.com/mwarning/device-observatory/tar.gz/v$(PKG_VERSION)?
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz

utils/device-observatory/patches/020-libmicrohttpd.patch

@@ -0,0 +1,20 @@
+--- a/src/webserver.c
++++ b/src/webserver.c
+@@ -129,7 +129,7 @@ const char *get_mimetype(const char str[])
+   return "application/octet-stream";
+ }
+ 
+-static int send_response(void *cls, struct MHD_Connection *connection,
++static enum MHD_Result send_response(void *cls, struct MHD_Connection *connection,
+   const char *url, const char *method, const char *version,
+   const char *upload_data, size_t *upload_data_size, void **con_cls)
+ {
+@@ -142,7 +142,7 @@ static int send_response(void *cls, struct MHD_Connection *connection,
+   struct device *device;
+   int is_localhost;
+   FILE *fp;
+-  int ret;
++  enum MHD_Result ret;
+ 
+   connection_info = MHD_get_connection_info(connection, MHD_CONNECTION_INFO_CLIENT_ADDRESS);
+   if (!connection_info) {