Lately (I think since maildir-utils was upgrade to v1.12.0, but I'm not entirely sure) I've been encountering segmentation fault with the `mu index` command. The backtrace is as follow (email address redacted):

> (gdb) bt
> #0  0x00000007f2e3801d in ?? ()
> #1  0x00007f2e3e369e7f in ?? () from /lib64/libpcre2-8.so.0
> #2  0x00007f2e3e3c6fa4 in pcre2_match_data_create_8 ()
>    from /lib64/libpcre2-8.so.0
> #3  0x00007f2e3ef0be41 in ?? () from /lib64/libglib-2.0.so.0
> #4  0x00007f2e3ef0c7f6 in g_regex_match_full ()
>    from /lib64/libglib-2.0.so.0
> #5  0x00007f2e3ef0c96a in g_regex_match () from /lib64/libglib-2.0.so.0
> #6  0x000055e2480607d9 in Mu::Regex::matches (
>     this=0x55e2480c65a0 <_ZL8email_rx.lto_priv.0>,
>     str="some.one@email.dev", mflags=G_REGEX_MATCH_DEFAULT)
>     at ../lib/utils/mu-regex.hh:142
> #7  Mu::Contact::has_valid_email (this=0x7f2e3801d4e0)
>     at ../lib/message/mu-contact.cc:74
> #8  0x000055e24803081d in Mu::ContactsCache::add (contact=...,
>     this=<optimized out>) at ../lib/mu-contacts-cache.cc:179
> #9  Mu::ContactsCache::add (personal=<synthetic pointer>: <optimized out>,
>     contacts=..., this=<optimized out>) at ../lib/mu-contacts-cache.cc:233
> #10 Mu::Store::add_message (this=<optimized out>, msg=...,
>     is_new=<optimized out>) at ../lib/mu-store.cc:338
> #11 0x000055e248040772 in Mu::Indexer::Private::add_message (
>     path="/home/user/mail/rd/BPF/new/0.001234.bpf-0-...", this=0x55e248975a30) at ../lib/mu-indexer.cc:255
> #12 Mu::Indexer::Private::item_worker (this=0x55e248975a30)
>     at ../lib/mu-indexer.cc:277
> #13 0x00007f2e3e4ec344 in ?? () from /lib64/libstdc++.so.6
> #14 0x00007f2e3e092bb2 in start_thread () from /lib64/libc.so.6
> #15 0x00007f2e3e11400c in clone3 () from /lib64/libc.so.6

The above is seen on maildir-utils-1.12.2, libpcre2-8-0-10.43, and libglib-2_0-0-2.80.0.