trouble with liblzmadec0.2.so

[fenugrec]

Hi,
I'm not sure what the root cause is for this , if it's even due to this script :

$ bitrock-unpacker xc8-v2.31-full-install-linux-x64-installer.run test
couldn't load file "/tmp/tcl_1f91Mv": /tmp/tcl_1f91Mv: failed to map segment from shared object
    while executing
"load /installer/libraries/lzma-decoder-linux-x64/liblzmadec0.2.so"
    ("package ifneeded Tcllzmadec 0.2" script)
    invoked from within
"package require Tcllzmadec"
    (file "/usr/bin/bitrock-unpacker" line 24)

Any ideas where to look ? I'm not even sure who is supposed to provide "tcllzmadec" ... I do have sdx and tclkit installed but those are blobs with no obvious package list.