docker: correctly escape $BACKEND in the help output

In Makefiles the $ must be escaped as $$ in shell uses.

Since 8a2390a4f47:

 $ make docker
     [...]
     NETWORK=1            Enable virtual network interface with default backend.
     NETWORK=ACKEND     Enable virtual network interface with ACKEND.

Once escaped:

 $ make docker
     [...]
     NETWORK=1            Enable virtual network interface with default backend.
     NETWORK=$BACKEND     Enable virtual network interface with $BACKEND.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-Id: <20171108024719.8389-1-f4bug@amsat.org>
Signed-off-by: Fam Zheng <famz@redhat.com>

diff --git a/tests/docker/Makefile.include b/tests/docker/Makefile.include
index f1a398e9fa65d7bc2bb7cff99fcbda46953f9a54..de87341528890b6fd036e80ea128a12cd99a726e 100644 (file)
--- a/tests/docker/Makefile.include
+++ b/tests/docker/Makefile.include
@@ -109,7 +109,7 @@ docker:
        @echo '    DEBUG=1              Stop and drop to shell in the created container'
        @echo '                         before running the command.'
        @echo '    NETWORK=1            Enable virtual network interface with default backend.'
-       @echo '    NETWORK=$BACKEND     Enable virtual network interface with $BACKEND.'
+       @echo '    NETWORK=$$BACKEND     Enable virtual network interface with $$BACKEND.'
        @echo '    NOUSER               Define to disable adding current user to containers passwd.'
        @echo '    NOCACHE=1            Ignore cache when build images.'
        @echo '    EXECUTABLE=<path>    Include executable in image.'