Mark BROKEN: fails to build

(cd /wrkdirs/usr/ports/games/burrtools/work/burrtools-0.6.3 && /bin/cat burricons.ico | winicontoppm -bestqual | pnmtopng -transparent=black > burricons.png)
winicontoppm: abnormal bit per pixel value 32
pnmtopng: Error reading first byte of what is expected to be a Netpbm magic number. Most often, this means your input file is empty

Reported by: pkg-fallout
MFH: 2020Q3