Try to put all the version stamps into common version_base.h
and version_stamp.h header files. All the source programs then
get their version from these header files.
Also handle the version stamps in the man pages by using the
version_*.h header file contents to edit the version strings
in the man page title bar markers.
(cherry picked from commit 966e29db3b)
Conflicts:
driver/iverilog.man.in
iverilog-vpi.man.in
version_base.in
vpi/vams_simparam.c
vvp/vvp.man.in
Ole Henrik Jahren
Stephen Williams