After talking to Bruce Evans and reading more standards specs,

After talking to Bruce Evans and reading more standards specs,
switch to using C99-style comments everywhere in preprocessed
assembler.  The reason is that lines starting with the regexp
'^[[:space:]]#' are treated as preprocessing directives, and
while it seems to work now with GCC, it's not necessarily has
to work.  Use C99 comments `//' for the trailing comments to
save whitespace.