This shouldn't have anything to do with GCC(?). At least for my tests hdparm 9.64 with the patch applied compiled fine on two systems, one with glibc 2.35 and one with glibc 2.36 where it failed to build without the patch.
Patch: Do not hardcode the pkg-config command
Works fine with the patch you've pushed to master, thanks!
Allow overriding of CC/CXX
Makefile patch fixing various build related issues
0.34.0 fails to compile tests
Works fine in QjackCtl 0.4.4, thanks for taking care of it! Bug can be closed.
Works fine in Qtractor 0.8.0, thanks for taking care of it! Bug can be closed.