Use different packages for darwin vs linux

This change creates two small files to split oci layer unpacking into a
new function that allows for different behavior based on platform.

NOTE: umoci v0.4.2 is used to prevent an a dependency issue with
github.com/opencontainers/runtime-spec v1.0.0 not being backwards
compatable

Update apptainer#3921 to most recent master

go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/Microsoft/hcsshim v0.8.6 // indirect
 	github.com/Netflix/go-expect v0.0.0-20180928190340-9d1f4485533b
 	github.com/alexflint/go-filemutex v0.0.0-20171028004239-d358565f3c3f // indirect
+	github.com/apex/log v1.1.1 // indirect
 	github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973 // indirect
 	github.com/bitly/go-simplejson v0.5.0 // indirect
 	github.com/blang/semver v3.5.1+incompatible
@@ -24,6 +25,7 @@ require (
 	github.com/containers/storage v0.0.0-20180604200230-88d80428f9b1 // indirect
 	github.com/coreos/go-iptables v0.3.0 // indirect
 	github.com/coreos/go-systemd v0.0.0-20180511133405-39ca1b05acc7 // indirect
+	github.com/cyphar/filepath-securejoin v0.2.2 // indirect
 	github.com/d2g/dhcp4 v0.0.0-20170904100407-a1d1b6c41b1c // indirect
 	github.com/d2g/dhcp4client v0.0.0-20180611075603-e61299896203 // indirect
 	github.com/d2g/dhcp4server v0.0.0-20181031114812-7d4a0a7f59a5 // indirect
@@ -34,7 +36,9 @@ require (
 	github.com/docker/docker-credential-helpers v0.6.0 // indirect
 	github.com/docker/go-connections v0.3.0 // indirect
 	github.com/docker/go-metrics v0.0.0-20180209012529-399ea8c73916 // indirect
+	github.com/docker/go-units v0.3.3 // indirect
 	github.com/docker/libtrust v0.0.0-20160708172513-aabc10ec26b7 // indirect
+	github.com/dsnet/compress v0.0.1 // indirect
 	github.com/fatih/color v1.7.0
 	github.com/garyburd/redigo v1.6.0 // indirect
 	github.com/ghodss/yaml v1.0.0 // indirect
@@ -45,40 +49,44 @@ require (
 	github.com/gorilla/mux v1.6.2 // indirect
 	github.com/gorilla/websocket v1.4.0
 	github.com/gotestyourself/gotestyourself v2.2.0+incompatible // indirect
+	github.com/hashicorp/errwrap v0.0.0-20141028054710-7554cd9344ce // indirect
 	github.com/hashicorp/go-cleanhttp v0.5.1 // indirect
+	github.com/hashicorp/go-multierror v0.0.0-20171204182908-b7773ae21874 // indirect
 	github.com/imdario/mergo v0.3.7 // indirect
 	github.com/j-keck/arping v0.0.0-20160618110441-2cf9dc699c56 // indirect
 	github.com/juju/errors v0.0.0-20190207033735-e65537c515d7 // indirect
 	github.com/juju/loggo v0.0.0-20190526231331-6e530bcce5d8 // indirect
 	github.com/juju/testing v0.0.0-20190613124551-e81189438503 // indirect
 	github.com/kardianos/osext v0.0.0-20190222173326-2bc1f35cddc0 // indirect
+	github.com/klauspost/pgzip v1.2.1 // indirect
 	github.com/kr/pty v1.1.8
 	github.com/kubernetes-sigs/cri-o v0.0.0-20180917213123-8afc34092907
-	github.com/mattn/go-colorable v0.1.1 // indirect
 	github.com/mattn/go-runewidth v0.0.2 // indirect
 	github.com/mattn/go-shellwords v1.0.3 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
 	github.com/mtrmac/gpgme v0.0.0-20170102180018-b2432428689c // indirect
 	github.com/onsi/ginkgo v1.8.0 // indirect
-	github.com/onsi/gomega v1.5.0 // indirect
-	github.com/openSUSE/umoci v0.4.4
+	github.com/openSUSE/umoci v0.4.2
 	github.com/opencontainers/go-digest v1.0.0-rc1
-	github.com/opencontainers/image-spec v1.0.0
+	github.com/opencontainers/image-spec v0.0.0-20180411145040-e562b0440392
+	github.com/opencontainers/image-tools v0.0.0-20180129025323-c95f76cbae74
 	github.com/opencontainers/runc v0.1.1 // indirect
-	github.com/opencontainers/runtime-spec v1.0.0
-	github.com/opencontainers/runtime-tools v0.7.0
+	github.com/opencontainers/runtime-spec v0.0.0-20180913141938-5806c3563733
+	github.com/opencontainers/runtime-tools v0.6.0
 	github.com/opencontainers/selinux v1.0.0-rc1
-	github.com/pelletier/go-toml v1.4.0
+	github.com/pelletier/go-toml v1.2.0
 	github.com/phayes/freeport v0.0.0-20180830031419-95f893ade6f2 // indirect
 	github.com/pkg/errors v0.8.1
 	github.com/pquerna/ffjson v0.0.0-20171002144729-d49c2bc1aa13 // indirect
 	github.com/prometheus/client_golang v0.0.0-20180607123607-faf4ec335fe0 // indirect
 	github.com/prometheus/client_model v0.0.0-20171117100541-99fa1f4be8e5 // indirect
 	github.com/prometheus/common v0.0.0-20180518154759-7600349dcfe1 // indirect
 	github.com/prometheus/procfs v0.0.0-20180612222113-7d6f385de8be // indirect
+	github.com/rootless-containers/proto v0.1.0 // indirect
 	github.com/safchain/ethtool v0.0.0-20180504150752-6e3f4faa84e1 // indirect
 	github.com/satori/go.uuid v1.2.0
 	github.com/seccomp/libseccomp-golang v0.9.0
+	github.com/sirupsen/logrus v1.0.5 // indirect
 	github.com/spf13/cobra v0.0.5
 	github.com/spf13/pflag v1.0.3
 	github.com/stevvooe/resumable v0.0.0-20180830230917-22b14a53ba50 // indirect
@@ -87,13 +95,20 @@ require (
 	github.com/sylabs/scs-key-client v0.3.0-0.20190509220229-bce3b050c4ec
 	github.com/sylabs/scs-library-client v0.3.0
 	github.com/sylabs/sif v1.0.6
+	github.com/syndtr/gocapability v0.0.0-20180223013746-33e07d32887e // indirect
+	github.com/urfave/cli v1.21.0 // indirect
+	github.com/vbatts/go-mtree v0.4.4 // indirect
 	github.com/vishvananda/netlink v1.0.1-0.20190618143317-99a56c251ae6 // indirect
 	github.com/vishvananda/netns v0.0.0-20171111001504-be1fbeda1936 // indirect
+	github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f // indirect
+	github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 // indirect
+	github.com/xeipuuv/gojsonschema v0.0.0-20180618132009-1d523034197f // indirect
 	github.com/xenolf/lego v2.5.0+incompatible // indirect
 	github.com/yvasiyarov/go-metrics v0.0.0-20150112132944-c25f46c4b940 // indirect
 	github.com/yvasiyarov/gorelic v0.0.6 // indirect
 	github.com/yvasiyarov/newrelic_platform_go v0.0.0-20160601141957-9c099fbc30e9 // indirect
-	golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2
+	go4.org v0.0.0-20180417224846-9599cf28b011 // indirect
+	golang.org/x/crypto v0.0.0-20190426145343-a29dc8fdc734
 	golang.org/x/sys v0.0.0-20190222072716-a9d3bda3a223
 	golang.org/x/time v0.0.0-20190308202827-9d24e82272b4 // indirect
 	google.golang.org/grpc v1.20.0 // indirect
@@ -109,8 +124,6 @@ require (
 
 replace (
 	github.com/Sirupsen/logrus => github.com/sirupsen/logrus v1.0.5
-	github.com/opencontainers/image-spec => github.com/opencontainers/image-spec v0.0.0-20180411145040-e562b0440392
-	github.com/opencontainers/runtime-spec => github.com/opencontainers/runtime-spec v0.0.0-20180913141938-5806c3563733
+	github.com/opencontainers/image-tools => github.com/sylabs/image-tools v0.0.0-20181006203805-2814f4980568
 	golang.org/x/crypto => github.com/sylabs/golang-x-crypto v0.0.0-20181006204705-4bce89e8e9a9
-
 )