[PATCH] kbuild: dtc: use env to resolve echo

[Michael Olbrich]

On Thu, Jan 20, 2022 at 09:56:49AM +0100, Sascha Hauer wrote:
> On Thu, Jan 20, 2022 at 08:47:33AM +0100, Rouven Czerwinski wrote:
> > Posix does not mandate to have binaries within a certain path, but
> > rather that the utilities may be available. Use env to resolve and call
> > echo from PATH.
> > 
> > Fixes: 2ae7ac7ab2f1 ("kbuild: dtc: Allow adding device tree fragments via config")
> > 
> > Signed-off-by: Rouven Czerwinski <r.czerwinski at pengutronix.de>
> > ---
> >  scripts/Makefile.lib | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> > index 13b1789c01..94ca1b771b 100644
> > --- a/scripts/Makefile.lib
> > +++ b/scripts/Makefile.lib
> > @@ -340,7 +340,7 @@ dts-frags = $(subst $(quote),,$(CONFIG_EXTERNAL_DTS_FRAGMENTS))
> >  quiet_cmd_dtc = DTC     $@
> >  # For compatibility between make 4.2 and 4.3
> >  H := \#
> > -cmd_dtc = /bin/echo -e '$(H)define $(subst -,_,$(*F))_dts 1\n'$(foreach f,$< $(dts-frags),'$(H)include "$(f)"\n') | \
> 
> Why hardcode /bin/echo anyway and not use plain 'echo' instead. I assume
> because echo can be a shell builtin, but are there shells out there
> where the builtin is not enough?

The builtin echo implementations are not very compatible. Better use printf
instead. For example, echo from dash (the default /bin/sh in Debian) does
not support '-e'.

Michael

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