Environment variables and command line arguments for Emacs can be set by modifying the STR# resources 128 and 129, respectively. A common environment variable that one may want to set is HOME.
The way to set an environment variable is by adding a string of the form
ENV_VAR=VALUE |
to resource STR# number 128 using ResEdit. To set up the program to use unibyte characters exclusively, for example, add the string
EMACS_UNIBYTE=1 |