localedef/ctype.sh requires sed -E for no reason
The introduction of ctype.sh in cset 13399:a1d28d03839f added a dependency on illumos sed's -E option for extended regex (inherited from FreeBSD). -E was not previously supported by Solaris sed and this has led to an additional bootstrapping step on some platforms (announced as a "flag day"). The use of -E seems to have been purely a stylistic decision as the same sed commands can use basic RE with only minor syntax changes (brackets for char matches, backslash before parens for substrings). The script itself also look like could be simplified.