Format to MHD coding style

Follow [GNU Coding Standards](https://www.gnu.org/prep/standards/standards.html).

    indent -nbad -bap -nbc -bbo -bl -bli2 -bls -ncdb -nce -cp1 -cs -di2 \
           -ndj -nfc1 -nfca -hnl -i2 -ip5 -lp -pcs -psl -nsc -nsob