[tlbuild] icu-60.2 in TL

[Karl Berry]

    icupkg is still being invoked 

I guess this is normal and unavoidable. I went back to the original 2017
sources, on my centos, and it also runs icupkg to create
./out/tmp/icudata.lst.

    The failure of icupkg (not even ./icupkg --help works)

Seems there is nothing to do but run it under the debugger and see
where/how it fails.

Couldn't hurt to check the ldd (or equivalent) results on the icupkg
binary.  Sometimes I have had to set LD_LIBRARY_PATH, since we don't do
the CXXHACK stuff for it. -k