This configure option causes the installed commands to have
a suffix string that makes them distinct from other versions
that also have a suffix string. This allows for multiple
installed versions of Icarus Verilog.
Also, move installed C/C++ header files into a subdirectory of
their own under the target include directory, to make clearer
the purpose and source of those files.
(cherry picked from commit 4bc90f7cfd)
146f64992c