jsoncpp: enable nativesdk build

This is necessary for unbundled build of protobuf.

Signed-off-by: Peter Marko <peter.marko@siemens.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-devtools/jsoncpp/jsoncpp_1.9.6.bb

@@ -22,4 +22,4 @@ inherit cmake
 
 EXTRA_OECMAKE += "-DBUILD_SHARED_LIBS=ON -DBUILD_OBJECT_LIBS=OFF -DJSONCPP_WITH_TESTS=OFF"
 
-BBCLASSEXTEND = "native"
+BBCLASSEXTEND = "native nativesdk"