The version of mawk shipped with bullseye still has this bug (or what
upstream calls a known limitation).
I've also verified that the bug occurs with upstream mawk, version
1.3.4-20200120, both with and without the --without-builtin-regex
compile time option.
unicorn:~/tmp/mawk-1.3.4-20200120$ ./configure --without-builtin-regex
[ output omitted ]
unicorn:~/tmp/mawk-1.3.4-20200120$ make
[ output omitted ]
unicorn:~/tmp/mawk-1.3.4-20200120$ echo 999999 | ./mawk '/^9{1}/'
unicorn:~/tmp/mawk-1.3.4-20200120$
(Output should have been 999999.)
Since it's failing even with --without-builtin-regex I figure this might
be something upstream should hear about, so I'm Cc-ing Mr. Dickey.
