This code in hdk/cl/examples/CL_TEMPLATE/build/scripts/synth_CL_TEMPLATE.tcl (and parallel files in other examples) is buggy:
# Reading the .sv and .v files, as proper designs would not require reading
# .vh, nor .inc files
read_verilog -sv [glob ${src_post_enc_dir}/*.?v]
In Tcl, glob *.?v does not match .v files as the ? does not work like in perl regular expressions, but like in shell globbing. It seems that to also match .v files, you need to say *.{s,}v.