grace 5.1.23
gqlplus 1.15
fix spacing
grepcidr 1.4
gtkwave 3.3.52
gzrt 0.8
httping 2.3.3
icon 9.5.1
imageworsener 1.1.0
plt-racket 5.3.6
Sometime between versions 5.2 and 5.3.6, `configure` began defaulting
to 64-bit.

Remove the `--enable-shared` configuration because PLT discourages it
and I'm not sure what it gives us.