my/protobuf-c: fix -Werror=unused-label for labels only used when compiling with IS_LITTLE_ENDIAN
my/protobuf-c: fix -Werror=unused-label for labels only used when compiling with IS_LITTLE_ENDIAN

hstern/wdns,hstern/nmsg,farsightsec/fstrm,snarkmaster/mtbl,hstern/nmsg,hstern/nmsg,rep/mtbl,snarkmaster/mtbl,rep/mtbl,rep/mtbl,hstern/nmsg,farsightsec/mtbl,hstern/wdns,farsightsec/fstrm,hstern/nmsg,hstern/wdns,hstern/wdns,farsightsec/mtbl,snarkmaster/mtbl