golang: fix build with oldish codesourcery amd64 toolchain (branch yem/go-west)

Hello All!

That toolchain seems to suffer from bug #20006

    https://sourceware.org/bugzilla/show_bug.cgi?id=20006

So, like bug 19615, introduce a config option for 20006, and mask away all golang packages.

Additionally, make golang packages abide by the number of CPUs to use.

Changes v1 -> v2:
- drop per-package dependency, move it to BR2_PACKAGE_HOST_GO_ARCH_SUPPORTS (Thomas)

Regards,
Yann E. MORIN.

The following changes since commit ea5280b889782e28b6bdf43e28b0e6a3a610f921

package/samba4: fix install of systemd files (2018-11-25 09:37:07 +0100)

are available in the git repository at:

git://git.buildroot.org/~ymorin/git/buildroot.git

for you to fetch changes up to d64c03d07584a8f48ab309fff66d2ee5661d5ee3

package: hide golang packages for toolchains with binutils bug 20006 (2018-11-25 09:54:23 +0100)

----------------------------------------------------------------
Yann E. MORIN (3):
infra/pkg-golang: enforce number of parallel jobs
toolchain: CodeSourcery AMD64 affected by PR20006
package: hide golang packages for toolchains with binutils bug 20006

 package/go/Config.in.host                                           | 1 +
 package/pkg-golang.mk                                               | 6 ++++--
 toolchain/Config.in                                                 | 5 +++++
 .../toolchain-external-codesourcery-amd64/Config.in                 | 1 +
 4 files changed, 11 insertions(+), 2 deletions(-)

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