Re: [PATCH] perf tools: Fix build error on read only source.

[Arnaldo Carvalho de Melo <acme@infradead.org>]

Em Wed, Aug 18, 2010 at 02:40:24PM +0200, Peter Zijlstra escreveu:
> On Wed, 2010-08-18 at 21:37 +0900, Kusanagi Kouichi wrote:
> 
> > With POSIX shell patch, $(OUTPUT) has not been created yet when it is
> > used by try-cc. This fixes the issue anyway.
> > 
> > diff --git a/tools/perf/Makefile b/tools/perf/Makefile
> > index dcb9700..5b1c12b 100644
> > --- a/tools/perf/Makefile
> > +++ b/tools/perf/Makefile
> > @@ -281,6 +281,7 @@ endif
> > 
> >  -include feature-tests.mak
> > 
> > +$(shell mkdir -p $(OUTPUT) 2> /dev/null)
> >  ifeq ($(call try-cc,$(SOURCE_HELLO),-Werror -fstack-protector-all),y)
> >  	CFLAGS := $(CFLAGS) -fstack-protector-all
> >  endif

> So you're wanting to provide a non-existing O=foo ?
> 
> I don't think we should, simply bail when it doesn't exist, kernel
> builds do the same:
> 
> # make O=plop-build bzImage
> /bin/sh: line 0: cd: plop-build: No such file or directory
> Makefile:117: *** output directory "plop-build" does not exist.  Stop.

Agreed that making it work like the kernel brings less surprises, but
isn't it convenient to be able to just do:

rm -rf ~/build
make O=~/build

and have everything work? Saving some keystrokes 8)

- Arnaldo