Without USE="extras" and pkg-config it builds fine, but with [extras] it fails if pkg-konfig is not installed: checking for GLIB... configure: error: in `/tmp/portage/sys-fs/udev-149/work/udev-149': configure: error: The pkg-config script could not be found or is too old. Make sure it is in your PATH or set the PKG_CONFIG environment variable to the full path to pkg-config. Alternatively, you may set the environment variables GLIB_CFLAGS and GLIB_LIBS to avoid the need to call pkg-config. See the pkg-config man page for more details. To get pkg-config, see <http://pkg-config.freedesktop.org/>. See `config.log' for more details. Reproducible: Always
udev needs pkg-config in DEPEND for getting glib-2.0 cflags/libs.
Fixed. Thanks for reporting.