core.c: loss of sign in implicit conversion fixed
core.c: loss of sign in implicit conversion fixed

src/core.c:2326:9: warning: Loss of sign in implicit conversion
                if (size >= value_buffer_size) {
                    ^~~~
src/core.c:2557:9: warning: Loss of sign in implicit conversion
                if (size >= value_buffer_size) {
                    ^~~~

ndmsystems/libndm