USE_EXPAND_UNPREFIXED="ARCH"
USE_EXPAND_IMPLICIT="ARCH ELIBC KERNEL USERLAND"
USE_EXPAND_VALUES_ARCH="alpha amd64 amd64-fbsd amd64-linux arm arm-linux arm64 hppa hppa-hpux ia64 ia64-hpux ia64-linux m68k m68k-mint mips nios2 ppc ppc64 ppc64-linux ppc-aix ppc-macos ppc-openbsd riscv s390 sh sparc sparc64-freebsd sparc64-solaris sparc-fbsd sparc-solaris x64-cygwin x64-freebsd x64-macos x64-openbsd x64-solaris x86 x86-cygwin x86-fbsd x86-freebsd x86-interix x86-linux x86-macos x86-netbsd x86-openbsd x86-solaris x86-winnt"
-USE_EXPAND_VALUES_ELIBC="AIX Cygwin Darwin DragonFly FreeBSD glibc HPUX Interix mintlib musl NetBSD OpenBSD SunOS uclibc Winnt"
+USE_EXPAND_VALUES_ELIBC="AIX bionic Cygwin Darwin DragonFly FreeBSD glibc HPUX Interix mintlib musl NetBSD OpenBSD SunOS uclibc Winnt"
USE_EXPAND_VALUES_KERNEL="AIX Darwin FreeBSD freemint HPUX linux NetBSD OpenBSD SunOS Winnt"
USE_EXPAND_VALUES_USERLAND="BSD GNU"
USE_EXPAND_UNPREFIXED="ARCH"
USE_EXPAND_IMPLICIT="ARCH ELIBC KERNEL USERLAND"
USE_EXPAND_VALUES_ARCH="alpha amd64 amd64-fbsd amd64-linux arm arm-linux arm64 hppa hppa-hpux ia64 ia64-hpux ia64-linux m68k m68k-mint mips nios2 ppc ppc64 ppc64-linux ppc-aix ppc-macos ppc-openbsd riscv s390 sh sparc sparc64-freebsd sparc64-solaris sparc-fbsd sparc-solaris x64-cygwin x64-freebsd x64-macos x64-openbsd x64-solaris x86 x86-cygwin x86-fbsd x86-freebsd x86-interix x86-linux x86-macos x86-netbsd x86-openbsd x86-solaris x86-winnt"
-USE_EXPAND_VALUES_ELIBC="AIX Cygwin Darwin DragonFly FreeBSD glibc HPUX Interix mintlib musl NetBSD OpenBSD SunOS uclibc Winnt"
+USE_EXPAND_VALUES_ELIBC="AIX bionic Cygwin Darwin DragonFly FreeBSD glibc HPUX Interix mintlib musl NetBSD OpenBSD SunOS uclibc Winnt"
USE_EXPAND_VALUES_KERNEL="AIX Darwin FreeBSD freemint HPUX linux NetBSD OpenBSD SunOS Winnt"
USE_EXPAND_VALUES_USERLAND="BSD GNU"