[Buildroot] [PATCH] swupdate: add upstream patch to fix build error

[Peter Korsgaard]

>>>>> "Jörg" == Jörg Krause <joerg.krause at embedded.rocks> writes:

 > When building SWUpdate with the following defconfig:
 > ```
 > CONFIG_DOWNLOAD=y
 > ```

 > .. the build process breaks with:

 > ```
 > corelib/channel_curl.c:27:10: fatal error: json-c/json.h: No such file or directory
 >  #include <json-c/json.h>
 > ```

 > Looking at the SWUpdate Kconfig based build system shows that `CONFIG_DOWNLOAD`
 > depends on `HAVE_LIBCURL`, which selects CURL, which eventually enables the
 > (unnecessary) build of channel_curl.o.

 > The upstream fixes the condition for building channel_curl.o by adding a new
 > hidden config option `CHANNEL_CURL`, which is only selected by the
 > dependent options.

 > Backported from:
 > https://github.com/sbabic/swupdate/commit/37a6666a532e9cbc42b56301f27919ae7c00d2eb

 > Signed-off-by: Jörg Krause <joerg.krause at embedded.rocks>

Committed, thanks.

-- 
Bye, Peter Korsgaard