I have embedded the perl interpreter in a C app and used
perl_parse(my_perl, argc, argv, env);
perl_parse(my_perl, xs_init, argc, argv, env);

where argv[1] = "perl_script.pl";
      argv[0] = c program's argv[0];
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then I do the "use My_Module;"

in perl_script.pl (it's just a wrapper for the module call)

You can set up @INC in perl_script.pl so that you can be sure to find your module.

I have not used a full path for perl_script.pl, but I'm pretty sure you could.