+@option{-M} option, above. Specifying the empty string as @var{mapfile}
+(that is, @code{-Map=}) causes the link map to be written to a file
+named after the @var{output} file, with @code{.map} appended.
+Specifying a directory as @var{mapfile} causes the link map to be
+written into a file inside the directory. The name of the file is
+again based upon the @var{output} filename with @code{.map} appended.