# See src/google/protobuf/stubs/platform_macros.h for supported archs.
  #
  # On PowerPC, the __atomic_*() built-ins for 1-byte, 2-byte and 4-byte
  # types are available built-in. However, the __atomic_*() built-ins for
  # 8-byte types is implemented via libatomic, so only available since gcc
  # 4.8.
  #
  # In Buildroot, to simplify things, we've decided to simply require gcc
  # 4.8 as soon as the architectures has at least one __atomic_*() built-in
  # variant that requires libatomic.
  #
  # Since protobuf most likely only uses the 1, 2 and 4-byte variants, it
  # *could* technically build with gcc 4.7. This is probably not a big deal,
  # and we can live with requiring gcc 4.8 on PowerPC to build protobuf. 
  #
  # The SPARC64 build fails due to a missing definition of Atomic64. This
  # has been fixed on the master branch but the build still breaks due to
  # undefined references to internal NoBarrier_Atomic*() functions.
  #
  # host-protobuf only builds on certain architectures
  config BR2_PACKAGE_PROTOBUF_ARCH_SUPPORTS
  	bool
  	default y if BR2_arm
  	default y if BR2_i386
  	default y if BR2_mipsel
  	default y if BR2_x86_64
  	default y if BR2_TOOLCHAIN_HAS_ATOMIC
  	depends on !BR2_sparc64 # missing definition of Atomic64
  	depends on BR2_HOSTARCH = "x86_64" || BR2_HOSTARCH = "x86"
  	depends on BR2_USE_MMU # fork()
  
  config BR2_PACKAGE_PROTOBUF
  	bool "protobuf"
  	depends on BR2_INSTALL_LIBSTDCPP
  	depends on BR2_TOOLCHAIN_HAS_THREADS
  	depends on BR2_PACKAGE_PROTOBUF_ARCH_SUPPORTS
  	depends on !BR2_STATIC_LIBS
  	help
  	  Protocol buffers are Google's language-neutral, platform-neutral,
  	  extensible mechanism for serializing structured data.
  
  	  https://developers.google.com/protocol-buffers
  
  comment "protobuf needs a toolchain w/ C++, threads, dynamic library"
  	depends on !BR2_INSTALL_LIBSTDCPP || !BR2_TOOLCHAIN_HAS_THREADS \
  		|| BR2_STATIC_LIBS
  	depends on BR2_PACKAGE_PROTOBUF_ARCH_SUPPORTS