Linux/ModelSim: can't access Tools > Edit preferences

This isn't a symlink problem - I removed the 'linux' symlink, and copied in the linuxaloem code, with the same result.

This is almost certainly a 32/64-bit problem, or a tcl version problem. The shared object which implements 'Tools>Edit preferences' is:

$ file /home/eda/modelsim/altera-18.0/modelsim_ase/linux/ScintillaTk/libScintillaTk1.12.so

/home/eda/modelsim/altera-18.0/modelsim_ase/linux/ScintillaTk/libScintillaTk1.12.so: ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), dynamically linked, not stripped

I'm on Centos/RH 6.2, x86_64, tclsh 8.5. Can someone at Intel please give me a definitive answer on what is supported? Do you actually have to run this on a 32-bit system?

Stack trace below, when 'Tools>Edit preferences' is clicked:

Couldn't load file "/home/eda/modelsim/altera-18.0/modelsim_ase/linux/ScintillaTk/libScintillaTk1.12.so": libstdc++.so.6: cannot open shared object file: No such file or directory

while executing

".vcop Eval Console::PrefDialog"

invoked from within

".#mBar.#mBar#tools invoke active"

("uplevel" body line 1)

invoked from within

"uplevel #0 [list $w invoke active]"

(procedure "tk::MenuInvoke" line 50)

invoked from within

"tk::MenuInvoke .#mBar.#mBar#tools 1"

(command bound to event)