This required keeping for-loops as actual things through the
netlist form so that the synthesizer can get at and understand
the parts of the for-loop. This may improve vvp code generation
in the future, but for now continue to present to the vvp code
generation the block-while form.
This patch covers more than it should. It removes many of the -Wextra
warnings in the main ivl directory. It also makes some minor code
improvements, adds support for constant logicals in eval_tree (&&/||),
adds support for correctly sign extending === and !==, it starts to
standardize the eval_tree debug messages and fixes a strength bug
in the target interface (found with -Wextra). The rest of the warnings
and eval_tree() rework will need to come as a second patch.
Rework the handling of file names to use a perm_string heap to hold
the file names, instead of the custom file name heap in the lexor.
Also rename the get_line to get_fileline to reflect its real duties.
This latter chage touched a lot of files.