ifndef MAKE
  MAKE := make
  endif
  ifndef HOSTMAKE
  HOSTMAKE = $(MAKE)
  endif
  HOSTMAKE := $(shell which $(HOSTMAKE) || type -p $(HOSTMAKE) || echo make)
  
  # If BR2_JLEVEL is 0, scale the maximum concurrency with the number of
  # CPUs. An additional job is used in order to keep processors busy
  # while waiting on I/O.
  # If the number of processors is not available, assume one.
  ifeq ($(BR2_JLEVEL),0)
  PARALLEL_JOBS := $(shell echo \
  	$$((1 + `getconf _NPROCESSORS_ONLN 2>/dev/null || echo 1`)))
  else
  PARALLEL_JOBS := $(BR2_JLEVEL)
  endif
  
  MAKE1 := $(HOSTMAKE) -j1
  override MAKE = $(HOSTMAKE) \
  	$(if $(findstring j,$(filter-out --%,$(MAKEFLAGS))),,-j$(PARALLEL_JOBS))
  
  ifeq ($(BR2_TOOLCHAIN_BUILDROOT),y)
  TARGET_VENDOR = $(call qstrip,$(BR2_TOOLCHAIN_BUILDROOT_VENDOR))
  else
  TARGET_VENDOR = buildroot
  endif
  
  # Sanity checks
  ifeq ($(TARGET_VENDOR),)
  $(error BR2_TOOLCHAIN_BUILDROOT_VENDOR is not allowed to be empty)
  endif
  ifeq ($(TARGET_VENDOR),unknown)
  $(error BR2_TOOLCHAIN_BUILDROOT_VENDOR cannot be 'unknown'. \
  	It might be confused with the native toolchain)
  endif
  
  # Compute GNU_TARGET_NAME
  GNU_TARGET_NAME = $(ARCH)-$(TARGET_VENDOR)-$(TARGET_OS)-$(LIBC)$(ABI)
  
  # FLAT binary format needs uclinux
  ifeq ($(BR2_BINFMT_FLAT),y)
  TARGET_OS = uclinux
  else
  TARGET_OS = linux
  endif
  
  ifeq ($(BR2_TOOLCHAIN_USES_UCLIBC),y)
  LIBC = uclibc
  else ifeq ($(BR2_TOOLCHAIN_USES_MUSL),y)
  LIBC = musl
  else
  LIBC = gnu
  endif
  
  # The ABI suffix is a bit special on ARM, as it needs to be
  # -uclibcgnueabi for uClibc EABI, and -gnueabi for glibc EABI.
  # This means that the LIBC and ABI aren't strictly orthogonal,
  # which explains why we need the test on LIBC below.
  ifeq ($(BR2_arm)$(BR2_armeb),y)
  ifeq ($(LIBC),uclibc)
  ABI = gnueabi
  else
  ABI = eabi
  endif
  
  ifeq ($(BR2_ARM_EABIHF),y)
  ABI := $(ABI)hf
  endif
  endif
  
  # For FSL PowerPC there's SPE
  ifeq ($(BR2_powerpc_SPE),y)
  ABI = spe
  # MPC8540s are e500v1 with single precision FP
  ifeq ($(BR2_powerpc_8540),y)
  TARGET_ABI += -mabi=spe -mfloat-gprs=single -Wa,-me500
  endif
  ifeq ($(BR2_powerpc_8548),y)
  TARGET_ABI += -mabi=spe -mfloat-gprs=double -Wa,-me500x2
  endif
  ifeq ($(BR2_powerpc_e500mc),y)
  TARGET_ABI += -mabi=spe -mfloat-gprs=double -Wa,-me500mc
  endif
  endif
  
  # Use longcalls option for Xtensa globally.
  # The 'longcalls' option allows calls across a greater range of addresses,
  # and is required for some packages. While this option can degrade both
  # code size and performance, the linker can usually optimize away the
  # overhead when a call ends up within a certain range.
  #
  # Use auto-litpools for Xtensa globally.
  # Collecting literals into separate section can be advantageous if that
  # section is placed into DTCM at link time. This is applicable for code
  # running on bare metal, but makes no sense under linux, where userspace
  # is isolated from the physical memory details. OTOH placing literals into
  # separate section breaks build of huge source files, because l32r
  # instruction can only access literals in 256 KBytes range.
  #
  ifeq ($(BR2_xtensa),y)
  TARGET_ABI += -mlongcalls -mauto-litpools
  endif
  
  ifeq ($(BR2_arc)$(BR2_ARC_ATOMIC_EXT),yy)
  TARGET_ABI += -matomic
  endif
  
  STAGING_SUBDIR = usr/$(GNU_TARGET_NAME)/sysroot
  STAGING_DIR    = $(HOST_DIR)/$(STAGING_SUBDIR)
  
  ifeq ($(BR2_OPTIMIZE_0),y)
  TARGET_OPTIMIZATION = -O0
  endif
  ifeq ($(BR2_OPTIMIZE_1),y)
  TARGET_OPTIMIZATION = -O1
  endif
  ifeq ($(BR2_OPTIMIZE_2),y)
  TARGET_OPTIMIZATION = -O2
  endif
  ifeq ($(BR2_OPTIMIZE_3),y)
  TARGET_OPTIMIZATION = -O3
  endif
  ifeq ($(BR2_OPTIMIZE_G),y)
  TARGET_OPTIMIZATION = -Og
  endif
  ifeq ($(BR2_OPTIMIZE_S),y)
  TARGET_OPTIMIZATION = -Os
  endif
  ifeq ($(BR2_DEBUG_1),y)
  TARGET_DEBUGGING = -g1
  endif
  ifeq ($(BR2_DEBUG_2),y)
  TARGET_DEBUGGING = -g2
  endif
  ifeq ($(BR2_DEBUG_3),y)
  TARGET_DEBUGGING = -g3
  endif
  
  TARGET_CPPFLAGS += -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64
  TARGET_CFLAGS = $(TARGET_CPPFLAGS) $(TARGET_ABI) $(TARGET_OPTIMIZATION) $(TARGET_DEBUGGING)
  TARGET_CXXFLAGS = $(TARGET_CFLAGS)
  TARGET_FCFLAGS = $(TARGET_ABI) $(TARGET_OPTIMIZATION) $(TARGET_DEBUGGING)
  TARGET_LDFLAGS = $(call qstrip,$(BR2_TARGET_LDFLAGS))
  
  ifeq ($(BR2_BINFMT_FLAT),y)
  TARGET_CFLAGS += $(if $($(PKG)_FLAT_STACKSIZE),-Wl$(comma)-elf2flt=-s$($(PKG)_FLAT_STACKSIZE),\
  	-Wl$(comma)-elf2flt)
  TARGET_CXXFLAGS += $(if $($(PKG)_FLAT_STACKSIZE),-Wl$(comma)-elf2flt=-s$($(PKG)_FLAT_STACKSIZE),\
  	-Wl$(comma)-elf2flt)
  TARGET_FCFLAGS += $(if $($(PKG)_FLAT_STACKSIZE),-Wl$(comma)-elf2flt=-s$($(PKG)_FLAT_STACKSIZE),\
  	-Wl$(comma)-elf2flt)
  TARGET_LDFLAGS += $(if $($(PKG)_FLAT_STACKSIZE),-Wl$(comma)-elf2flt=-s$($(PKG)_FLAT_STACKSIZE),-Wl$(comma)-elf2flt)
  endif
  
  ifeq ($(BR2_BINFMT_FLAT_SHARED),y)
  TARGET_LDFLAGS += -mid-shared-library -mshared-library-id=0
  TARGET_CFLAGS += -mid-shared-library -mshared-library-id=0
  TARGET_FCFLAGS += -mid-shared-library -mshared-library-id=0
  TARGET_CXXFLAGS += -mid-shared-library -mshared-library-id=0
  endif
  ifeq ($(BR2_BINFMT_FLAT_SEP_DATA),y)
  TARGET_LDFLAGS += -msep-data
  TARGET_CFLAGS += -msep-data
  TARGET_FCFLAGS += -msep-data
  TARGET_CXXFLAGS += -msep-data
  endif
  
  ifeq ($(BR2_SSP_REGULAR),y)
  TARGET_CFLAGS += -fstack-protector
  TARGET_CXXFLAGS += -fstack-protector
  TARGET_FCFLAGS += -fstack-protector
  else ifeq ($(BR2_SSP_STRONG),y)
  TARGET_CFLAGS += -fstack-protector-strong
  TARGET_CXXFLAGS += -fstack-protector-strong
  TARGET_FCFLAGS += -fstack-protector-strong
  else ifeq ($(BR2_SSP_ALL),y)
  TARGET_CFLAGS += -fstack-protector-all
  TARGET_CXXFLAGS += -fstack-protector-all
  TARGET_FCFLAGS += -fstack-protector-all
  endif
  
  ifeq ($(BR2_TOOLCHAIN_BUILDROOT),y)
  TARGET_CROSS = $(HOST_DIR)/usr/bin/$(GNU_TARGET_NAME)-
  else
  TARGET_CROSS = $(HOST_DIR)/usr/bin/$(call qstrip,$(BR2_TOOLCHAIN_EXTERNAL_PREFIX))-
  endif
  
  # Define TARGET_xx variables for all common binutils/gcc
  TARGET_AR       = $(TARGET_CROSS)ar
  TARGET_AS       = $(TARGET_CROSS)as
  TARGET_CC       = $(TARGET_CROSS)gcc
  TARGET_CPP      = $(TARGET_CROSS)cpp
  TARGET_CXX      = $(TARGET_CROSS)g++
  TARGET_FC       = $(TARGET_CROSS)gfortran
  TARGET_LD       = $(TARGET_CROSS)ld
  TARGET_NM       = $(TARGET_CROSS)nm
  TARGET_RANLIB   = $(TARGET_CROSS)ranlib
  TARGET_READELF  = $(TARGET_CROSS)readelf
  TARGET_OBJCOPY  = $(TARGET_CROSS)objcopy
  TARGET_OBJDUMP  = $(TARGET_CROSS)objdump
  
  ifeq ($(BR2_STRIP_strip),y)
  STRIP_STRIP_DEBUG := --strip-debug
  STRIP_STRIP_UNNEEDED := --strip-unneeded
  STRIP_STRIP_ALL := --strip-all
  TARGET_STRIP = $(TARGET_CROSS)strip
  STRIPCMD = $(TARGET_CROSS)strip --remove-section=.comment --remove-section=.note
  KSTRIPCMD = $(STRIPCMD) $(STRIP_STRIP_UNNEEDED)
  endif
  ifeq ($(BR2_STRIP_none),y)
  TARGET_STRIP = true
  STRIPCMD = $(TARGET_STRIP)
  KSTRIPCMD = $(TARGET_STRIP)
  endif
  INSTALL := $(shell which install || type -p install)
  FLEX := $(shell which flex || type -p flex)
  BISON := $(shell which bison || type -p bison)
  SED := $(shell which sed || type -p sed) -i -e
  UNZIP := $(shell which unzip || type -p unzip) -q
  
  APPLY_PATCHES = support/scripts/apply-patches.sh $(if $(QUIET),-s)
  
  HOST_CPPFLAGS  = -I$(HOST_DIR)/usr/include
  HOST_CFLAGS   ?= -O2
  HOST_CFLAGS   += $(HOST_CPPFLAGS)
  HOST_CXXFLAGS += $(HOST_CFLAGS)
  HOST_LDFLAGS  += -L$(HOST_DIR)/lib -L$(HOST_DIR)/usr/lib -Wl,-rpath,$(HOST_DIR)/usr/lib
  
  # host-intltool should be executed with the system perl, so we save
  # the path to the system perl, before a host-perl built by Buildroot
  # might get installed into $(HOST_DIR)/usr/bin and therefore appears
  # in our PATH. This system perl will be used as INTLTOOL_PERL.
  export PERL=$(shell which perl)
  
  # host-intltool needs libxml-parser-perl, which Buildroot installs in
  # $(HOST_DIR)/usr/lib/perl, so we must make sure that the system perl
  # finds this perl module by exporting the proper value for PERL5LIB.
  export PERL5LIB=$(HOST_DIR)/usr/lib/perl
  
  TARGET_CONFIGURE_OPTS = \
  	PATH=$(BR_PATH) \
  	AR="$(TARGET_AR)" \
  	AS="$(TARGET_AS)" \
  	LD="$(TARGET_LD)" \
  	NM="$(TARGET_NM)" \
  	CC="$(TARGET_CC)" \
  	GCC="$(TARGET_CC)" \
  	CPP="$(TARGET_CPP)" \
  	CXX="$(TARGET_CXX)" \
  	FC="$(TARGET_FC)" \
  	F77="$(TARGET_FC)" \
  	RANLIB="$(TARGET_RANLIB)" \
  	READELF="$(TARGET_READELF)" \
  	STRIP="$(TARGET_STRIP)" \
  	OBJCOPY="$(TARGET_OBJCOPY)" \
  	OBJDUMP="$(TARGET_OBJDUMP)" \
  	AR_FOR_BUILD="$(HOSTAR)" \
  	AS_FOR_BUILD="$(HOSTAS)" \
  	CC_FOR_BUILD="$(HOSTCC)" \
  	GCC_FOR_BUILD="$(HOSTCC)" \
  	CXX_FOR_BUILD="$(HOSTCXX)" \
  	LD_FOR_BUILD="$(HOSTLD)" \
  	CPPFLAGS_FOR_BUILD="$(HOST_CPPFLAGS)" \
  	CFLAGS_FOR_BUILD="$(HOST_CFLAGS)" \
  	CXXFLAGS_FOR_BUILD="$(HOST_CXXFLAGS)" \
  	LDFLAGS_FOR_BUILD="$(HOST_LDFLAGS)" \
  	FCFLAGS_FOR_BUILD="$(HOST_FCFLAGS)" \
  	DEFAULT_ASSEMBLER="$(TARGET_AS)" \
  	DEFAULT_LINKER="$(TARGET_LD)" \
  	CPPFLAGS="$(TARGET_CPPFLAGS)" \
  	CFLAGS="$(TARGET_CFLAGS)" \
  	CXXFLAGS="$(TARGET_CXXFLAGS)" \
  	LDFLAGS="$(TARGET_LDFLAGS)" \
  	FCFLAGS="$(TARGET_FCFLAGS)" \
  	FFLAGS="$(TARGET_FCFLAGS)" \
  	PKG_CONFIG="$(PKG_CONFIG_HOST_BINARY)" \
  	STAGING_DIR="$(STAGING_DIR)" \
  	INTLTOOL_PERL=$(PERL)
  
  TARGET_MAKE_ENV = PATH=$(BR_PATH)
  
  
  HOST_CONFIGURE_OPTS = \
  	PATH=$(BR_PATH) \
  	AR="$(HOSTAR)" \
  	AS="$(HOSTAS)" \
  	LD="$(HOSTLD)" \
  	NM="$(HOSTNM)" \
  	CC="$(HOSTCC)" \
  	GCC="$(HOSTCC)" \
  	CXX="$(HOSTCXX)" \
  	CPP="$(HOSTCPP)" \
  	OBJCOPY="$(HOSTOBJCOPY)" \
  	RANLIB="$(HOSTRANLIB)" \
  	CPPFLAGS="$(HOST_CPPFLAGS)" \
  	CFLAGS="$(HOST_CFLAGS)" \
  	CXXFLAGS="$(HOST_CXXFLAGS)" \
  	LDFLAGS="$(HOST_LDFLAGS)" \
  	PKG_CONFIG_ALLOW_SYSTEM_CFLAGS=1 \
  	PKG_CONFIG_ALLOW_SYSTEM_LIBS=1 \
  	PKG_CONFIG="$(PKG_CONFIG_HOST_BINARY)" \
  	PKG_CONFIG_SYSROOT_DIR="/" \
  	PKG_CONFIG_LIBDIR="$(HOST_DIR)/usr/lib/pkgconfig:$(HOST_DIR)/usr/share/pkgconfig" \
  	INTLTOOL_PERL=$(PERL)
  
  HOST_MAKE_ENV = \
  	PATH=$(BR_PATH) \
  	PKG_CONFIG="$(PKG_CONFIG_HOST_BINARY)" \
  	PKG_CONFIG_SYSROOT_DIR="/" \
  	PKG_CONFIG_LIBDIR="$(HOST_DIR)/usr/lib/pkgconfig"
  
  # This is extra environment we can not export ourselves (eg. because some
  # packages use that variable internally, eg. uboot), so we have to
  # explicitly pass it to user-supplied external hooks (eg. post-build,
  # post-images)
  EXTRA_ENV = \
  	PATH=$(BR_PATH) \
  	BR2_DL_DIR=$(BR2_DL_DIR) \
  	BUILD_DIR=$(BUILD_DIR) \
  	BR2_EXTERNAL=$(BR2_EXTERNAL)
  
  ################################################################################
  # settings we need to pass to configure
  
  # does unaligned access trap?
  BR2_AC_CV_TRAP_CHECK = ac_cv_lbl_unaligned_fail=yes
  ifeq ($(BR2_i386),y)
  BR2_AC_CV_TRAP_CHECK = ac_cv_lbl_unaligned_fail=no
  endif
  ifeq ($(BR2_x86_64),y)
  BR2_AC_CV_TRAP_CHECK = ac_cv_lbl_unaligned_fail=no
  endif
  ifeq ($(BR2_m68k),y)
  BR2_AC_CV_TRAP_CHECK = ac_cv_lbl_unaligned_fail=no
  endif
  ifeq ($(BR2_powerpc)$(BR2_powerpc64)$(BR2_powerpc64le),y)
  BR2_AC_CV_TRAP_CHECK = ac_cv_lbl_unaligned_fail=no
  endif
  
  ifeq ($(BR2_ENDIAN),"BIG")
  BR2_AC_CV_C_BIGENDIAN = ac_cv_c_bigendian=yes
  else
  BR2_AC_CV_C_BIGENDIAN = ac_cv_c_bigendian=no
  endif
  
  # AM_GNU_GETTEXT misdetects musl gettext support.
  # musl currently implements api level 1 and 2 (basic + ngettext)
  # http://www.openwall.com/lists/musl/2015/04/16/3
  ifeq ($(BR2_TOOLCHAIN_USES_MUSL),y)
  BR2_GT_CV_FUNC_GNUGETTEXT_LIBC = \
  	gt_cv_func_gnugettext1_libc=yes \
  	gt_cv_func_gnugettext2_libc=yes
  endif
  
  TARGET_CONFIGURE_ARGS = \
  	$(BR2_AC_CV_TRAP_CHECK) \
  	ac_cv_func_mmap_fixed_mapped=yes \
  	ac_cv_func_memcmp_working=yes \
  	ac_cv_have_decl_malloc=yes \
  	gl_cv_func_malloc_0_nonnull=yes \
  	ac_cv_func_malloc_0_nonnull=yes \
  	ac_cv_func_calloc_0_nonnull=yes \
  	ac_cv_func_realloc_0_nonnull=yes \
  	lt_cv_sys_lib_search_path_spec="" \
  	$(BR2_AC_CV_C_BIGENDIAN) \
  	$(BR2_GT_CV_FUNC_GNUGETTEXT_LIBC)
  
  ################################################################################
  
  ifeq ($(BR2_ENABLE_LOCALE),y)
  DISABLE_NLS :=
  else
  DISABLE_NLS :=--disable-nls
  endif
  
  ifneq ($(BR2_INSTALL_LIBSTDCPP),y)
  TARGET_CONFIGURE_OPTS += CXX=false
  endif
  
  ifeq ($(BR2_STATIC_LIBS),y)
  SHARED_STATIC_LIBS_OPTS = --enable-static --disable-shared
  TARGET_CFLAGS += -static
  TARGET_CXXFLAGS += -static
  TARGET_FCFLAGS += -static
  TARGET_LDFLAGS += -static
  else ifeq ($(BR2_SHARED_LIBS),y)
  SHARED_STATIC_LIBS_OPTS = --disable-static --enable-shared
  else ifeq ($(BR2_SHARED_STATIC_LIBS),y)
  SHARED_STATIC_LIBS_OPTS = --enable-static --enable-shared
  endif
  
  ifeq ($(BR2_COMPILER_PARANOID_UNSAFE_PATH),y)
  export BR_COMPILER_PARANOID_UNSAFE_PATH=enabled
  endif
  
  include package/pkg-download.mk
  include package/pkg-autotools.mk
  include package/pkg-cmake.mk
  include package/pkg-luarocks.mk
  include package/pkg-perl.mk
  include package/pkg-python.mk
  include package/pkg-virtual.mk
  include package/pkg-generic.mk
  include package/pkg-kconfig.mk
  include package/pkg-rebar.mk
  include package/pkg-kernel-module.mk