[Buildroot] [PATCH v3 5/6] package/flannel: Add BR2_TOOLCHAIN_HAS_THREADS

[Waldemar Brodkorb <wbx@openadk.org>]

Hi,
Thomas Petazzoni wrote,

> Hello,
> 
> On Tue, 31 May 2016 13:47:52 -0700, Geoff Levand wrote:
> 
> > Looking at the go sources, they force -pie when compiling cgo support
> > for ARM.  See line number 3188 in https://golang.org/src/cmd/go/build.go.
> 
> Can you get more details than the "get accurate imported sym" the code
> has?
> 
> > I think the only solution is to not build go packages that use cgo
> > when BR2_arm && BR2_TOOLCHAIN_USES_UCLIBC, so something like this:
> > 
> > +# cgo on ARM requires PIE linkage, which is not compatable with uClibc.
> > +comment "flannel is not available with uClibc-based toolchain on ARM architecture"
> > +       depends on BR2_PACKAGE_HOST_GO_ARCH_SUPPORTS
> > +       depends on BR2_TOOLCHAIN_HAS_THREADS
> > +       depends on BR2_arm && BR2_TOOLCHAIN_USES_UCLIBC
> > +
> >  config BR2_PACKAGE_FLANNEL
> >         bool "flannel"
> >         depends on BR2_PACKAGE_HOST_GO_ARCH_SUPPORTS
> >         depends on BR2_TOOLCHAIN_HAS_THREADS
> > +       depends on !(BR2_arm && BR2_TOOLCHAIN_USES_UCLIBC)
> >         help
> > 
> > If this looks OK, I'll submit a patch.
> 
> This is really annoying, as all Go packages that need cgo support will
> not work in what is probably Buildroot's most widely used
> configuration: ARM with uClibc.
> 
> So I'd really like to push things a bit further, and either fix uClibc
> so that static+PIE works, or understand why Go wants PIE on ARM.

A first step would be to integrate Scrt1.o into the external
toolchain packages. It is build when uClibc-ng SHARED is enabled
together with crt1.o.

best regards
 Waldemar