[PATCH v4 08/20] Add get_clone_versions and get_version functions.

This is a reimplementation of get_target_clone_attr_len, get_attr_str, and separate_attrs using string_slice and auto_vec to make memory management and use simpler. Adds get_target_version helper function to get the target_version string from a decl. gcc/c-family/ChangeLog: * c-attribs.c

[PATCH v4 08/20] Add get_clone_versions and get_version functions.

This is a reimplementation of get_target_clone_attr_len, get_attr_str, and separate_attrs using string_slice and auto_vec to make memory management and use simpler. Adds get_target_version helper function to get the target_version string from a decl. gcc/c-family/ChangeLog: * c-attribs.c