Add support for ignoring suffix characters in numeric conversions

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Introduce a new function strtol_with_suffix to convert a string to a long integer while allowing for certain suffix characters ('L', 'l', 'U', 'u') to be ignored. This function will return the long integer value from the string, or 0 if no valid conversion can be performed. It updates strtol calls in eval_unary to use this new function, improving handling of numeric inputs with suffixes.