[SeaBIOS] iasl-option not working

[Kevin O'Connor]

On Thu, Aug 30, 2012 at 08:38:06AM +0300, Michael S. Tsirkin wrote:
> On Wed, Aug 29, 2012 at 09:38:00PM -0400, Kevin O'Connor wrote:
> >  ################ DSDT build rules
> >  
> > -iasl-option=$(shell if "$(1)" "$(2)" -h > /dev/null 2>&1 \
> > +iasl-option=$(shell if test -z "`$(1) $(2) 2>&1 > /dev/null`" \
> >      ; then echo "$(2)"; else echo "$(3)"; fi ;)
> >  
> >  $(OUT)%.hex: src/%.dsl ./tools/acpi_extract_preprocess.py ./tools/acpi_extract.py
> 
> Will try. But logic seems fragile here: I am guessing old
> iasl versions exit with error if you run them without input,
> so this code relies on such to fail silently?
> But what if future iasl starts producing
> "Warning: no input" or such on stderr?
> Seems a sensible thing to do and will break this script.
> 
> How about we give it a small dummy input file
> instead and check exit status?

I agree with your statements on fragility, but I'm loathe to
complicate the Makefile that much.  I tested a bunch of iasl versions
and all seem to work with the check above.  For now I'm going to go
with this version.  Should iasl change in such a way that it breaks
this check, we can replace it with a test script in the tools/
directory.

-Kevin