IEEE Std 1003.1, 2004 Edition states:
"The escape sequence '\n' shall match a <newline> embedded in
the pattern space."
It is unclear whether this also applies to a \n embedded in a
character class. Disable the existing handling of \n in a character
class following Mac OS X, GNU sed version 4.1.5 with --posix, and
SunOS 5.10 /usr/bin/sed.
Pointed by: Marius Strobl
Obtained from: Mac OS X
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