$ tclsh

tclsh8.6 [/tmp] package require md4c 1.0
can't find package md4c 1.0
while evaluating package require md4c 1.0
tclsh8.6 [/tmp] package require md4c
can't find package md4c
while evaluating package require md4c
tclsh8.6 [/tmp] package require tcllibc
0.3.15
tclsh8.6 [/tmp] ::md4::md4c hello
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