[ebuild  N     ] dev-lang/mlton-20180207:0/20180207::gentoo USE="-binary -bootstrap-smlnj -doc -pax-kernel -stage3" 41.7 MiB
[ebuild  N     ] sci-mathematics/twelf-1.7.1-r2:0/1.7.1::gentoo USE="-doc -emacs -examples" 1.1 MiB

Total: 2 packages (2 new), Size of downloads: 42.8 MiB


 * Running sanity checks...
>>> dev-lang/mlton-20180207: failed pkg_pretend
 /Volumes/Disk 1/gentoo-prefix/usr/lib/pkgcore/lib/pkgcore/ebd/.generated/libs/7/pkg_pretend: line 145: [[: invalid regular expression `': empty (sub)expression
  * ERROR: dev-lang/mlton-20180207:: failed (pretend phase):
  *   USE flag 'binary' not in IUSE for dev-lang/mlton-20180207
  * 
  * Call stack:
  *    isolated-functions.bash, line  333:  called pkg_pretend
  *                ebuild.bash, line 1627:  called use '!binary'
  *                pkg_pretend, line  146:  called die
  * 
  * Working directory: '/var/tmp/portage'

!!! Sanity checks failed, exiting...