Fix txzchk linking: add -lm for floorl/floor#1377

gaidardzhiev wants to merge 1 commit intoioccc-src:masterioccc-src/mkiocccentry:masterfrom

gaidardzhiev:fix-txzchk-mathlibgaidardzhiev/mkiocccentry:fix-txzchk-mathlibCopy head branch name to clipboard