prom_setenv − set prom environment variable

#include <prom/entrypt.h>
prom_setenv(name, value)
char *name, *value;

may be called to define new prom environment variables or change the
value of existing environment variables.  The primary use of prom_setenv
is to allow programs to change the value of prom environment variables
maintained in non-volatile ram, see prom(1spp).
returns 0.
prom_getenv(2spp)