Resurrect macOS support

[okuoku]

cmake -GNinja -DYUNIBASE_TARGET_PREFIX=/opt/yunibase -DYUNIBASE_FIX_TIMESTAMPS=OFF "-DYUNIBASE_ONLY=GAUCHE;CHIBI_SCHEME;CHICKEN5;STKLOS;GAMBIT;FOMENT" ~/repos/yunibase

Current dependency:

devel/concurrencykit
pkgtools/pkg_alternatives
pkgtools/bootstrap-mk-files
devel/gmp
devel/boehm-gc
devel/cmake
joyent/pkgsrc-gnupg-keys
devel/pkgconf
textproc/oniguruma
lang/nawk
devel/ninja-build
devel/autoconf
x11/libX11
security/mozilla-rootcerts
devel/readline
textproc/nbsed
devel/gettext
sysutils/bsdinstall
devel/libtool
devel/pcre
pkgtools/pkg_install
devel/libltdl
pkgtools/pkgin
devel/automake
devel/bmake
pkgtools/cwrappers

[okuoku]

Started.