Portable '/proc/self/maps' as a data frame. Determine which library or
other region is mapped to a specific address of a process. -- R packages
can contain native code, compiled to shared libraries at build or
installation time. When loaded, each shared library occupies a portion of
the address space of the main process. When only a machine instruction
pointer is available (e.g. from a backtrace during error inspection or
profiling), the address space map determines which library this instruction
pointer corresponds to.
