+# The optional sixth argument is a list of exclusions used internally by
+# the compiler similar to exceptions. The difference being that exclusions
+# allow matching default options that genmultilib does not know about and
+# is done at runtime as opposed to being sorted out at compile time.
+# Each element in the list is a separate exclusion rule. Each rule is
+# a list of options (sans preceding '-') separated by a '/'. The options
+# on the rule are grouped as an AND operation, and all options much match
+# for the rule to exclude a set. Options can be preceded with a '!' to
+# match a logical NOT.
+
+# The optional seventh argument is a list of OS subdirectory names.
+# The format is either the same as of the second argument, or a set of
+# mappings. When it is the same as the second argument, it describes
+# the multilib directories using OS conventions, rather than GCC
+# conventions. When it is a set of mappings of the form gccdir=osdir,
+# the left side gives the GCC convention and the right gives the
+# equivalent OS defined location. If the osdir part begins with a !,
+# the os directory names are used exclusively. Use the mapping when
+# there is no one-to-one equivalence between GCC levels and the OS.
+
+# The last option should be "yes" if multilibs are enabled. If it is not
+# "yes", all GCC multilib dir names will be ".".
+