package/boost: Boost.Atomic needs atomic intrinsics

similar to previous problems with nios2 and not-available atomic ints
the build for Boost.Atomics also fails for ARC Targets which don't
have the ATOMICS_EXT flag set.

according to [0] "Boost.Atomic has a hard requirement of the native
atomic operations on bytes". The same tests mentioned there fail for
ARC without the atomic extension.

Disable BR2_TOOLCHAIN_SUPPORTS_ALWAYS_LOCKFREE_ATOMIC_INTS for BR2_arc
without BR2_ARC_ATOMIC_EXT.

Fixes:
  http://autobuild.buildroot.net/results/4ca54a85672d7b9328b1909b457e548c6032a493

[0] https://github.com/boostorg/atomic/issues/42#issuecomment-734130348

Signed-off-by: Michael Nosthoff <buildroot@heine.tech>
[Arnout: add to BR2_TOOLCHAIN_SUPPORTS_ALWAYS_LOCKFREE_ATOMIC_INTS
         instead of updating all packages]
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>
(cherry picked from commit ad71b415c1bdf1bbf4c37b04c772dc3104187b58)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

toolchain/Config.in

@@ -100,6 +100,7 @@ config BR2_TOOLCHAIN_SUPPORTS_ALWAYS_LOCKFREE_ATOMIC_INTS
 	depends on !BR2_ARM_CPU_ARMV5
 	depends on !BR2_sparc_v8
 	depends on !BR2_m68k_cf5208
+	depends on !(BR2_arc && !BR2_ARC_ATOMIC_EXT)
 
 # GCC uses thunk functions to adjust the 'this' pointer when calling
 # C++ member functions in classes derived with multiple inheritance.