unxz chrashes when build with M2-Planet

[stikonas]

For some reason unxz from mescc-tools-extra crashes when it is build with M2-Planet.

Luckily this is not super big problem when bootstrapping later stages as we can rebuild unxz with e.g. tcc.

(gdb) bt
#0  0x0000000000625658 in _END_IF_main_29 ()
#1  0x0000000000000000 in ?? ()