OpenPGP card not available

[Dan Fandrich]

Running "gpg --card-status" with a configured Yubikey plugged in on an x86_64
Linux machine just gives me these errors when running 2.4.5:

gpg: selecting card failed: No such device
gpg: OpenPGP card not available: No such device

However, leaving everything else the same and just running 2.2.42 (& earlier
2.2.x) gives me the output I'd expect with that command.  I've tried some of
the advice I've found of adding "reader-port Yubico Yubi" and "pcsc-shared" to
scdaemon.conf didn't make a difference. Enabling some scdaemon logging shows
this interesting bit in the log file:

2024-04-08 16:45:28 scdaemon[62168] DBG: chan_7 <- SERIALNO
2024-04-08 16:45:28 scdaemon[62168] DBG: apdu_open_reader: BAI=70202
2024-04-08 16:45:28 scdaemon[62168] DBG: apdu_open_reader: new device=70202
2024-04-08 16:45:28 scdaemon[62168] ccid open error: skip
2024-04-08 16:45:28 scdaemon[62168] DBG: chan_7 -> ERR 100696144 No such device <SCD>

With 2.2.42, I see this (with an actual serial number) and all works well:

2024-04-08 16:38:43 scdaemon[36563] DBG: chan_7 <- SERIALNO
2024-04-08 16:38:43 scdaemon[36563] DBG: apdu_open_reader: BAI=70202
2024-04-08 16:38:43 scdaemon[36563] DBG: apdu_open_reader: new device=70202
2024-04-08 16:38:43 scdaemon[36563] ccid open error: skip
2024-04-08 16:38:43 scdaemon[36563] DBG: chan_7 -> S SERIALNO D0000000000000000000000000000000
2024-04-08 16:38:43 scdaemon[36563] DBG: chan_7 -> OK
...

Running "echo SERIALNO | scd/scdaemon --server" is enough.  I've tried both
pcsc-lite 1.9.9 and 2.0.3 without a difference.  I'm not sure how to drill
down to figure out further to figure out what else could be causing the
failure. One obvious difference is that the working version is linked against
libpthread.so.0 but the failing one is linked against libnpth.so.0, but that
seems to have to do with locking which I wouldn't expect to make difference
with a simple local test.

I was hoping to bisect to the problem except that the 2.3 and 2.4 branches fail
at their .0 versions. Does someone have a suggestion to debug further?

Dan