These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.10 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/libserialport-0.1.2-r1::gentoo  USE="-static-libs" 460 KiB
[ebuild  N     ] dev-libs/libusb-1.0.30:1::gentoo  USE="-debug -doc -examples -static-libs -test -udev -verify-sig" 641 KiB
[ebuild  N     ] virtual/libusb-1-r2:1::gentoo  USE="-udev" 0 KiB
[ebuild  N     ] dev-libs/hidapi-0.15.0::gentoo  USE="-doc" 356 KiB
[ebuild  N     ] dev-libs/libusb-compat-0.1.9::gentoo  USE="(split-usr) -debug -examples" 322 KiB
[ebuild  N     ] virtual/libusb-0-r2::gentoo  0 KiB
[ebuild  N     ] dev-embedded/avrdude-8.3:0/5::gentoo  USE="python readline -ftdi -gpiod" PYTHON_SINGLE_TARGET="python3_14 -python3_12 -python3_13" 6414 KiB

Total: 7 packages (7 new), Size of downloads: 8191 KiB