[gnome-continuous-yocto/gnomeostree-3.28-rocko: 3699/8267] oe-buildenv-internal: show usage output

[Emmanuele Bassi <ebassi src gnome org>]

commit a5438f8f74cc9117f9766cd255c3e32e793dd3dc
Author: Ed Bartosh <ed bartosh linux intel com>
Date:   Fri Dec 9 19:26:48 2016 +0200

    oe-buildenv-internal: show usage output
    
    Show usage text if script is not sourced.
    Tested in bash, zsh and dash.
    
    [YOCTO #10751]
    
    (From OE-Core rev: ac7a905b18acb8bd9b2412b6682afbe1d7e18d7b)
    
    Signed-off-by: Ed Bartosh <ed bartosh linux intel com>
    Signed-off-by: Ross Burton <ross burton intel com>
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 scripts/oe-buildenv-internal |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/scripts/oe-buildenv-internal b/scripts/oe-buildenv-internal
index 9fae3b4..c890552 100755
--- a/scripts/oe-buildenv-internal
+++ b/scripts/oe-buildenv-internal
@@ -18,6 +18,18 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
+if ! $(return >/dev/null 2>&1) ; then
+    echo 'oe-buildenv-internal: error: this script must be sourced'
+    echo ''
+    echo 'Usage: . $OEROOT/scripts/oe-buildenv-internal &&'
+    echo ''
+    echo 'OpenEmbedded oe-buildenv-internal - an internal script that is'
+    echo 'used in oe-init-build-env and oe-init-build-env-memres to'
+    echo 'initialize oe build environment'
+    echo ''
+    exit 2
+fi
+
 # It is assumed OEROOT is already defined when this is called
 if [ -z "$OEROOT" ]; then
     echo >&2 "Error: OEROOT is not defined!"