Fix iconv and tests on Mac.

The Mac iconv_open(3) doesn't follow Unicode TR#22 rules for charset
alias matching that bionic and glibc do (and, strictly, POSIX doesn't
say you have to even though it's obviously a good idea), so we have
to say exactly "UTF-8" rather than "utf8".

Additionally, the 2006-era bash 3.2 on current versions of macOS
(because it was the last GPLv2 bash) seems to have bugs that cause
it to mangle UTF-8 input, so we can't reliably echo a UTF-8 sequence
into a file. Use \x in the tests to work around this.

0 files changed, 0 insertions, 0 deletions