function::print_usyms - Print out user stack from string
String with list of hexadecimal (user) addresses
This function performs a symbolic lookup of the addresses in the given string,
which are assumed to be the result of prior calls to ustack,
ucallers, and similar functions.
Prints one line per address, including the address, the name of
the function containing the address, and an estimate of its position within
that function, as obtained by usymdata. Returns nothing.