[OE-core] [PATCH] perf: Add LDFLAGS to allow build of old kernels without patching

[Richard Purdie]

On Wed, 2013-09-18 at 11:54 -0400, Bruce Ashfield wrote:
> On Wed, Sep 18, 2013 at 11:44 AM, Enrico Scholz
> <enrico.scholz at sigma-chemnitz.de> wrote:
> > Otavio Salvador <otavio at ossystems.com.br> writes:
> >
> >> I don't agree on this. perf is tied to kernel and part of its code so
> >> I think same exception rule apply for it as well.
> >
> > perf ships with the kernel but is a pure userspace program.  It does not
> > require any special setup ('make configure'), it links against complex
> > userspace gui frameworks and uses userspace headers.
> 
> yes, we realize this .. we have a long a complicated history with perf and the
> related build issues.
> 
> We are stating our general policy, interfere with it's build as little
> as possible.
> Use extension variables, not clobber variables, etc.
> 
> Otherwise, we end up creating our own issues, and have the bugs to prove it :)

For the record, I do think Enrico does have a valid point here. We do
put things in CFLAGS and LDFLAGS which we expect *all* userspace to be
built with. Things like the hash style, preferred debugging symbol
options and so on are expected to be used for all userspace binaries.

So somehow we do need to ensure that when the kernel is building
userspace binaries, it does use the options we expect and match the rest
of the system.

Equally, I do understand the kernel build system is a complex beast in
its own right.

We don't have to solve this instantly, but in general its considered a
bug if things like the hash-style in LDFLAGS don't make it to the linker
commandline. We do have QA tests that check for this, however they don't
function as they used to since we hard set the option on when we compile
the linker now :/.

Cheers,

Richard