workaround to ltscale

Librecad makes the fig 1 but I want something like fig 2.

In AutoCAD the command is ltscale.

Just use a different linetype, in 1:100 dash small or dash tiny will do it. But you can't scale the line type to your desire. You can change the line type by modify - properties  (and select the line). Or by modify - attributes. Allows you to select multiple entities ( finish selection with 'enter').