A lot of failure recently:

https://cros-goldeneye.corp.google.com/chromeos/healthmonitoring/buildDetails?buildbucketId=8930293278740096448

https://cros-goldeneye.corp.google.com/chromeos/legoland/builderHistory?buildConfig=tael-paladin&buildBranch=master

It looks like it reproduces in ToT when I build locally:

../../xorg-server-1.20.1/config/udev.c:126:49: error: implicit declaration of function 'major' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
        if (xf86_find_platform_device_by_devnum(major(devnum), minor(devnum)))
                                                ^
../../xorg-server-1.20.1/config/udev.c:126:49: warning: this function declaration is not a prototype [-Wstrict-prototypes]
../../xorg-server-1.20.1/config/udev.c:126:64: error: implicit declaration of function 'minor' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
        if (xf86_find_platform_device_by_devnum(major(devnum), minor(devnum)))
                                                               ^


I'm guessing this was an existing package error, but it may have been hidden by some linux-headers behavior (e.g., old linux-headers didn't force you to include <sys/sysmacros.h>, but now that we're rev-bumping linux-headers again, rebuilds are uncovering the error?). This CL is in most (?) of the failing runs:

https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/1324989