This absolute include causes a build failure on Linux for me:
.../cheri/freebsd/contrib/nvi/cl/../common/common.h:10:10: fatal error: '/usr/include/db.h' file not found
#include "/usr/include/db.h" /* Only include db1. */
This change patches the file to use #include <db.h> instead until a
solution has been found upstream. See also https://github.com/lichray/nvi2/issues/69