[Buildroot] [PATCH] Makefile: test if dot exists before using it in graph-depends

[Peter Korsgaard]

>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni at free-electrons.com> writes:

 > The 'graph-depends' logic uses the 'dot' program from Graphviz to draw
 > the dependency graph, but it doesn't check its existence before
 > starting the generation of the graph, which can lead to user confusion
 > as reported in:

 >  http://lists.busybox.net/pipermail/buildroot/2014-June/099278.html

 > With this commit, we first test if the 'dot' program is available, and
 > if it's not, we error out with a clear error message:

 > $ make graph-depends
 > ERROR: The 'dot' program from Graphviz is needed for graph-depends
 > make: *** [graph-depends] Error 1

 > Reported-by: Dallas Clement <dallas.a.clement at gmail.com>
 > Cc: Dallas Clement <dallas.a.clement at gmail.com>
 > Cc: Yann E. MORIN <yann.morin.1998 at free.fr>
 > Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
 > ---
 >  Makefile | 2 ++
 >  1 file changed, 2 insertions(+)

 > diff --git a/Makefile b/Makefile
 > index 5501068..db8fd15 100644
 > --- a/Makefile
 > +++ b/Makefile
 > @@ -674,6 +674,8 @@ graph-build: $(O)/build/build-time.log
 >  				   $(if $(BR2_GRAPH_ALT),--alternate-colors)$(sep))
 
 >  graph-depends:
 > +	@dot -? >/dev/null 2>&1 || \
 > +		(echo "ERROR: The 'dot' program from Graphviz is needed for graph-depends"; exit 1)

Error messages should go to stderr, not stdout.

Committed with that fixed, thanks.

-- 
Bye, Peter Korsgaard