If you are using warnings and strict as in your script you can check %INC (perlvar) for those modules, for example:

if (exists($INC{'strict.pm'})) { print "strict\n" }
if (exists($INC{'warnings.pm'})) { print "warnings\n" }
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Warnings can also be switched on with the -w command line option, and this is what $^W is used for. In this case just test for truth. So for warnings you may need:

if (exists($INC{'warnings.pm'}) || $^W) {print "Warnings\n"};
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