toolchain: introduce BR2_TOOLCHAIN_HAS_BINUTILS_BUG_21464
The OpenRISC binutils is affected by a linker bug (binutils bug 21464)
for which no workaround exists. This causes build breakage in a number
of packages, so this commit introduces a
BR2_TOOLCHAIN_HAS_BINUTILS_BUG_21464 option to identify this bug. As
all binutils versions are affected, this option is true whenever the
configuration targets OpenRISC.
The bug was already reported and it's been recently updated:
https://sourceware.org/bugzilla/show_bug.cgi?id=21464
Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>