build error on macos

[notedit]

../media-server/include/config.h:44:20: note: expanded from macro 'FD_INVALID'
#define FD_INVALID      (int)-1
                        ^
../media-server/src/rtp/RTPPacket.cpp:240:55: error: call to unavailable member function 'value': introduced in macOS
      10.14
                auto vp8NewPayloadDescriptor = vp8PayloadDescriptor.value();