build/core/init.mk - platform/gdk - Git at Google

 GDK_LOG := $(strip $(GDK_LOG))

 # Check that we have at least GNU Make 3.81
 # We do this by detecting whether 'lastword' is supported
 #
 MAKE_TEST := $(lastword a b c d e f)
 ifneq ($(MAKE_TEST),f)
     $(error Android GDK: GNU Make version $(MAKE_VERSION) is too low (should be >= 3.81))
 endif
 ifdef GDK_LOG
     $(info Android GDK: GNU Make version $(MAKE_VERSION) detected)
 endif

 # GDK_ROOT *must* be defined and point to the root of the GDK installation
 GDK_ROOT := $(strip $(GDK_ROOT))
 ifndef GDK_ROOT
     $(error ERROR while including init.mk: GDK_ROOT must be defined !)
 endif
 ifneq ($(words $(GDK_ROOT)),1)
     $(info,The Android GDK installation path contains spaces: '$(GDK_ROOT)')
     $(error,Please fix the problem by reinstalling to a different location.)
 endif

 # ====================================================================
 #
 # Define a few useful variables and functions.
 # More stuff will follow in definitions.mk.
 #
 # ====================================================================

 # Used to output warnings and error from the library, it's possible to
 # disable any warnings or errors by overriding these definitions
 # manually or by setting GDK_NO_WARNINGS or GDK_NO_ERRORS

 __gdk_name    := Android GDK
 __gdk_info     = $(info $(__gdk_name): $1 $2 $3 $4 $5)
 __gdk_warning  = $(warning $(__gdk_name): $1 $2 $3 $4 $5)
 __gdk_error    = $(error $(__gdk_name): $1 $2 $3 $4 $5)

 ifdef GDK_NO_WARNINGS
 __gdk_warning :=
 endif
 ifdef GDK_NO_ERRORS
 __gdk_error :=
 endif

 # -----------------------------------------------------------------------------
 # Function : gdk_log
 # Arguments: 1: text to print when GDK_LOG is defined
 # Returns  : None
 # Usage    : $(call gdk_log,<some text>)
 # -----------------------------------------------------------------------------
 ifdef GDK_LOG
 gdk_log = $(info $(__gdk_name): $1)
 else
 gdk_log :=
 endif

 # ====================================================================
 #
 # Host system auto-detection.
 #
 # ====================================================================

 #
 # Determine host system and architecture from the environment
 #
 HOST_OS := $(strip $(HOST_OS))
 ifndef HOST_OS
     # On all modern variants of Windows (including Cygwin and Wine)
     # the OS environment variable is defined to 'Windows_NT'
     #
     # The value of PROCESSOR_ARCHITECTURE will be x86 or AMD64
     #
     ifeq ($(OS),Windows_NT)
         HOST_OS := windows
     else
         # For other systems, use the `uname` output
         UNAME := $(shell uname -s)
         ifneq (,$(findstring Linux,$(UNAME)))
             HOST_OS := linux
         endif
         ifneq (,$(findstring Darwin,$(UNAME)))
             HOST_OS := darwin
         endif
         # We should not be there, but just in case !
         ifneq (,$(findstring CYGWIN,$(UNAME)))
             HOST_OS := windows
         endif
         ifeq ($(HOST_OS),)
             $(call __gdk_info,Unable to determine HOST_OS from uname -s: $(UNAME))
             $(call __gdk_info,Please define HOST_OS in your environment.)
             $(call __gdk_error,Aborting.)
         endif
     endif
     $(call gdk_log,Host OS was auto-detected: $(HOST_OS))
 else
     $(call gdk_log,Host OS from environment: $(HOST_OS))
 endif

 HOST_ARCH := $(strip $(HOST_ARCH))
 ifndef HOST_ARCH
     ifeq ($(HOST_OS),windows)
         HOST_ARCH := $(PROCESSOR_ARCHITECTURE)
         ifeq ($(HOST_ARCH),AMD64)
             HOST_ARCH := x86
         endif
     else # HOST_OS != windows
         UNAME := $(shell uname -m)
         ifneq (,$(findstring 86,$(UNAME)))
             HOST_ARCH := x86
         endif
         # We should probably should not care at all
         ifneq (,$(findstring Power,$(UNAME)))
             HOST_ARCH := ppc
         endif
         ifeq ($(HOST_ARCH),)
             $(call __gdk_info,Unsupported host architecture: $(UNAME))
             $(call __gdk_error,Aborting)
         endif
     endif # HOST_OS != windows
     $(call gdk_log,Host CPU was auto-detected: $(HOST_ARCH))
 else
     $(call gdk_log,Host CPU from environment: $(HOST_ARCH))
 endif

 HOST_TAG := $(HOST_OS)-$(HOST_ARCH)

 # The directory separator used on this host
 HOST_DIRSEP := :

 # For now always use ":" since Windows is Cygwin
 #ifeq ($(HOST_OS),windows)
 #  HOST_DIRSEP := ;
 #endif

 # If we are on Windows, we need to check that we are not running
 # Cygwin 1.5, which is deprecated and won't run our toolchain
 # binaries properly.
 #
 ifeq ($(HOST_TAG),windows-x86)
     # On cygwin, 'uname -r' returns something like 1.5.23(0.225/5/3)
     # We recognize 1.5. as the prefix to look for then.
     CYGWIN_VERSION := $(shell uname -r)
     ifneq ($(filter XX1.5.%,XX$(CYGWIN_VERSION)),)
         $(call __gdk_info,You seem to be running Cygwin 1.5, which is not supported.)
         $(call __gdk_info,Please upgrade to Cygwin 1.7 or higher.)
         $(call __gdk_error,Aborting.)
     endif
     # special-case the host-tag
     HOST_TAG := windows
 endif
 $(call gdk_log,HOST_TAG set to $(HOST_TAG))

 #
 # Verify that the 'awk' tool has the features we need.
 # Both Nawk and Gawk do.
 #
 HOST_AWK := $(strip $(HOST_AWK))
 ifndef HOST_AWK
     HOST_AWK := awk
     $(call gdk_log,Host awk tool was auto-detected: $(HOST_AWK))
 else
     $(call gdk_log,Host awk tool from environment: $(HOST_AWK))
 endif

 # Location of all awk scripts we use
 BUILD_AWK := $(GDK_ROOT)/build/awk

 AWK_TEST := $(shell $(HOST_AWK) -f $(BUILD_AWK)/check-awk.awk)
 $(call gdk_log,Host awk test returned: $(AWK_TEST))
 ifneq ($(AWK_TEST),Pass)
     $(call __gdk_info,Host awk tool is outdated. Please define HOST_AWK to point to Gawk or Nawk !)
     $(call __gdk_error,Aborting.)
 endif

 #
 # On windows, define the 'cygwin-to-host-path' function here depending on the
 # environment. The rules are the following:
 #
 # 1/ If "cygpath' is not in your path, do not use it at all. It looks like
 #    this allows to build with the GDK from MSys without problems.
 #
 # 2/ Since invoking 'cygpath -m' from GNU Make for each source file is
 #    _very_ slow, try to generate a Make function that performs the mapping
 #    from cygwin to host paths through simple substitutions.
 #
 # 3/ In case we fail horribly, allow the user to define GDK_USE_CYGPATH to '1'
 #    in order to use 'cygpath -m' nonetheless. This is only a backup plan in
 #    case our automatic substitution function doesn't work (only likely if you
 #    have a very weird cygwin setup).
 #
 # The function for 2/ is generated by an awk script. It's really a series
 # of nested patsubst calls, that look like:
 #
 #     cygwin-to-host-path = $(patsubst /cygdrive/c/%,c:/%,\
 #                             $(patsusbt /cygdrive/d/%,d:/%, \
 #                              $1)
 #
 # except that the actual definition is built from the list of mounted
 # drives as reported by "mount" and deals with drive letter cases (i.e.
 # '/cygdrive/c' and '/cygdrive/C')
 #
 ifeq ($(HOST_OS),windows)
     CYGPATH := $(strip $(HOST_CYGPATH))
     ifndef CYGPATH
         $(call gdk_log, Probing for 'cygpath' program)
         CYGPATH := $(strip $(shell which cygpath 2>/dev/null))
         ifndef CYGPATH
             $(call gdk_log, 'cygpath' was *not* found in your path)
         else
             $(call gdk_log, 'cygpath' found as: $(CYGPATH))
         endif
     endif
     ifndef CYGPATH
         cygwin-to-host-path = $1
     else
         ifeq ($(GDK_USE_CYGPATH),1)
             $(call gdk_log, Forced usage of 'cygpath -m' through GDK_USE_CYGPATH=1)
             cygwin-to-host-path = $(strip $(shell $(CYGPATH) -m $1))
         else
             # Call an awk script to generate a Makefile fragment used to define a function
             WINDOWS_HOST_PATH_FRAGMENT := $(shell mount | $(HOST_AWK) -f $(BUILD_AWK)/gen-windows-host-path.awk)
             ifeq ($(GDK_LOG),1)
                 $(info Using cygwin substitution rules:)
                 $(eval $(shell mount | $(HOST_AWK) -f $(BUILD_AWK)/gen-windows-host-path.awk -vVERBOSE=1))
             endif
             $(eval cygwin-to-host-path = $(WINDOWS_HOST_PATH_FRAGMENT))
         endif
     endif
 endif # HOST_OS == windows

 # The location of the build system files
 BUILD_SYSTEM := $(GDK_ROOT)/build/core

 # Include common definitions
 include $(BUILD_SYSTEM)/definitions.mk

 # ====================================================================
 #
 # Read all toolchain-specific configuration files.
 #
 # Each toolchain must have a corresponding config.mk file located
 # in build/toolchains/<name>/ that will be included here.
 #
 # Each one of these files should define the following variables:
 #   TOOLCHAIN_NAME   toolchain name (e.g. arm-eabi-4.2.1)
 #   TOOLCHAIN_ABIS   list of target ABIs supported by the toolchain.
 #
 # Then, it should include $(ADD_TOOLCHAIN) which will perform
 # book-keeping for the build system.
 #
 # ====================================================================

 # the build script to include in each toolchain config.mk
 ADD_TOOLCHAIN := $(BUILD_SYSTEM)/add-toolchain.mk

 # the list of all toolchains in this GDK
 GDK_ALL_TOOLCHAINS :=
 GDK_ALL_ABIS       :=

 TOOLCHAIN_CONFIGS := $(wildcard $(GDK_ROOT)/toolchains/*/config.mk)
 $(foreach _config_mk,$(TOOLCHAIN_CONFIGS),\
   $(eval include $(BUILD_SYSTEM)/add-toolchain.mk)\
 )

 GDK_ALL_TOOLCHAINS   := $(call remove-duplicates,$(GDK_ALL_TOOLCHAINS))
 GDK_ALL_ABIS         := $(call remove-duplicates,$(GDK_ALL_ABIS))

 # The default toolchain is now arm-eabi-4.4.0, however its
 # C++ compiler is a tad bit more pedantic with certain
 # constructs (e.g. templates) so allow users to switch back
 # to the old 4.2.1 instead if they really want to.
 #
 # NOTE: you won't get armeabi-v7a support though !
 #
 GDK_TOOLCHAIN := $(strip $(GDK_TOOLCHAIN))
 ifdef GDK_TOOLCHAIN
     # check that the toolchain name is supported
     $(if $(filter-out $(GDK_ALL_TOOLCHAINS),$(GDK_TOOLCHAIN)),\
       $(call __gdk_info,GDK_TOOLCHAIN is defined to the unsupported value $(GDK_TOOLCHAIN)) \
       $(call __gdk_info,Please use one of the following values: $(GDK_ALL_TOOLCHAINS))\
       $(call __gdk_error,Aborting)\
     ,)
     $(call gdk_log, Using specific toolchain $(GDK_TOOLCHAIN))
 endif

 $(call gdk_log, This GDK supports the following toolchains and target ABIs:)
 $(foreach tc,$(GDK_ALL_TOOLCHAINS),\
     $(call gdk_log, $(space)$(space)$(tc):  $(GDK_TOOLCHAIN.$(tc).abis))\
 )

 # ====================================================================
 #
 # Read all platform-specific configuration files.
 #
 # Each platform must be located in build/platforms/android-<apilevel>
 # where <apilevel> corresponds to an API level number, with:
 #   3 -> Android 1.5
 #   4 -> next platform release
 #
 # ====================================================================

 # The platform files were moved in the Android source tree from
 # $TOP/gdk/build/platforms to $TOP/development/gdk/platforms. However,
 # the official GDK release packages still place them under the old
 # location for now, so deal with this here
 #
 GDK_PLATFORMS_ROOT := $(strip $(GDK_PLATFORMS_ROOT))
 ifndef GDK_PLATFORMS_ROOT
     GDK_PLATFORMS_ROOT := $(strip $(wildcard $(GDK_ROOT)/platforms))
     ifndef GDK_PLATFORMS_ROOT
         GDK_PLATFORMS_ROOT := $(strip $(wildcard $(GDK_ROOT)/build/platforms))
     endif

     ifndef GDK_PLATFORMS_ROOT
         $(call __gdk_info,Could not find platform files (headers and libraries))
         $(if $(strip $(wildcard $(GDK_ROOT)/RELEASE.TXT)),\
             $(call __gdk_info,Please define GDK_PLATFORMS_ROOT to point to a valid directory.)\
         ,\
             $(call __gdk_info,Please run build/tools/build-platforms.sh to build the corresponding directory.)\
         )
         $(call __gdk_error,Aborting)
     endif

     $(call gdk_log,Found platform root directory: $(GDK_PLATFORMS_ROOT))
 endif
 ifeq ($(strip $(wildcard $(GDK_PLATFORMS_ROOT)/android-*)),)
     $(call __gdk_info,Your GDK_PLATFORMS_ROOT points to an invalid directory)
     $(call __gdk_info,Current value: $(GDK_PLATFORMS_ROOT))
     $(call __gdk_error,Aborting)
 endif

 GDK_ALL_PLATFORMS := $(strip $(notdir $(wildcard $(GDK_PLATFORMS_ROOT)/android-*)))
 $(call gdk_log,Found supported platforms: $(GDK_ALL_PLATFORMS))

 $(foreach _platform,$(GDK_ALL_PLATFORMS),\
   $(eval include $(BUILD_SYSTEM)/add-platform.mk)\
 )
	GDK_LOG := $(strip $(GDK_LOG))

	# Check that we have at least GNU Make 3.81
	# We do this by detecting whether 'lastword' is supported
	#
	MAKE_TEST := $(lastword a b c d e f)
	ifneq ($(MAKE_TEST),f)
	$(error Android GDK: GNU Make version $(MAKE_VERSION) is too low (should be >= 3.81))
	endif
	ifdef GDK_LOG
	$(info Android GDK: GNU Make version $(MAKE_VERSION) detected)
	endif

	# GDK_ROOT must be defined and point to the root of the GDK installation
	GDK_ROOT := $(strip $(GDK_ROOT))
	ifndef GDK_ROOT
	$(error ERROR while including init.mk: GDK_ROOT must be defined !)
	endif
	ifneq ($(words $(GDK_ROOT)),1)
	$(info,The Android GDK installation path contains spaces: '$(GDK_ROOT)')
	$(error,Please fix the problem by reinstalling to a different location.)
	endif

	# ====================================================================
	#
	# Define a few useful variables and functions.
	# More stuff will follow in definitions.mk.
	#
	# ====================================================================

	# Used to output warnings and error from the library, it's possible to
	# disable any warnings or errors by overriding these definitions
	# manually or by setting GDK_NO_WARNINGS or GDK_NO_ERRORS

	__gdk_name := Android GDK
	__gdk_info = $(info $(__gdk_name): $1 $2 $3 $4 $5)
	__gdk_warning = $(warning $(__gdk_name): $1 $2 $3 $4 $5)
	__gdk_error = $(error $(__gdk_name): $1 $2 $3 $4 $5)

	ifdef GDK_NO_WARNINGS
	__gdk_warning :=
	endif
	ifdef GDK_NO_ERRORS
	__gdk_error :=
	endif

	# -----------------------------------------------------------------------------
	# Function : gdk_log
	# Arguments: 1: text to print when GDK_LOG is defined
	# Returns : None
	# Usage : $(call gdk_log,<some text>)
	# -----------------------------------------------------------------------------
	ifdef GDK_LOG
	gdk_log = $(info $(__gdk_name): $1)
	else
	gdk_log :=
	endif

	# ====================================================================
	#
	# Host system auto-detection.
	#
	# ====================================================================

	#
	# Determine host system and architecture from the environment
	#
	HOST_OS := $(strip $(HOST_OS))
	ifndef HOST_OS
	# On all modern variants of Windows (including Cygwin and Wine)
	# the OS environment variable is defined to 'Windows_NT'
	#
	# The value of PROCESSOR_ARCHITECTURE will be x86 or AMD64
	#
	ifeq ($(OS),Windows_NT)
	HOST_OS := windows
	else
	# For other systems, use the `uname` output
	UNAME := $(shell uname -s)
	ifneq (,$(findstring Linux,$(UNAME)))
	HOST_OS := linux
	endif
	ifneq (,$(findstring Darwin,$(UNAME)))
	HOST_OS := darwin
	endif
	# We should not be there, but just in case !
	ifneq (,$(findstring CYGWIN,$(UNAME)))
	HOST_OS := windows
	endif
	ifeq ($(HOST_OS),)
	$(call __gdk_info,Unable to determine HOST_OS from uname -s: $(UNAME))
	$(call __gdk_info,Please define HOST_OS in your environment.)
	$(call __gdk_error,Aborting.)
	endif
	endif
	$(call gdk_log,Host OS was auto-detected: $(HOST_OS))
	else
	$(call gdk_log,Host OS from environment: $(HOST_OS))
	endif

	HOST_ARCH := $(strip $(HOST_ARCH))
	ifndef HOST_ARCH
	ifeq ($(HOST_OS),windows)
	HOST_ARCH := $(PROCESSOR_ARCHITECTURE)
	ifeq ($(HOST_ARCH),AMD64)
	HOST_ARCH := x86
	endif
	else # HOST_OS != windows
	UNAME := $(shell uname -m)
	ifneq (,$(findstring 86,$(UNAME)))
	HOST_ARCH := x86
	endif
	# We should probably should not care at all
	ifneq (,$(findstring Power,$(UNAME)))
	HOST_ARCH := ppc
	endif
	ifeq ($(HOST_ARCH),)
	$(call __gdk_info,Unsupported host architecture: $(UNAME))
	$(call __gdk_error,Aborting)
	endif
	endif # HOST_OS != windows
	$(call gdk_log,Host CPU was auto-detected: $(HOST_ARCH))
	else
	$(call gdk_log,Host CPU from environment: $(HOST_ARCH))
	endif

	HOST_TAG := $(HOST_OS)-$(HOST_ARCH)

	# The directory separator used on this host
	HOST_DIRSEP := :

	# For now always use ":" since Windows is Cygwin
	#ifeq ($(HOST_OS),windows)
	# HOST_DIRSEP := ;
	#endif

	# If we are on Windows, we need to check that we are not running
	# Cygwin 1.5, which is deprecated and won't run our toolchain
	# binaries properly.
	#
	ifeq ($(HOST_TAG),windows-x86)
	# On cygwin, 'uname -r' returns something like 1.5.23(0.225/5/3)
	# We recognize 1.5. as the prefix to look for then.
	CYGWIN_VERSION := $(shell uname -r)
	ifneq ($(filter XX1.5.%,XX$(CYGWIN_VERSION)),)
	$(call __gdk_info,You seem to be running Cygwin 1.5, which is not supported.)
	$(call __gdk_info,Please upgrade to Cygwin 1.7 or higher.)
	$(call __gdk_error,Aborting.)
	endif
	# special-case the host-tag
	HOST_TAG := windows
	endif
	$(call gdk_log,HOST_TAG set to $(HOST_TAG))

	#
	# Verify that the 'awk' tool has the features we need.
	# Both Nawk and Gawk do.
	#
	HOST_AWK := $(strip $(HOST_AWK))
	ifndef HOST_AWK
	HOST_AWK := awk
	$(call gdk_log,Host awk tool was auto-detected: $(HOST_AWK))
	else
	$(call gdk_log,Host awk tool from environment: $(HOST_AWK))
	endif

	# Location of all awk scripts we use
	BUILD_AWK := $(GDK_ROOT)/build/awk

	AWK_TEST := $(shell $(HOST_AWK) -f $(BUILD_AWK)/check-awk.awk)
	$(call gdk_log,Host awk test returned: $(AWK_TEST))
	ifneq ($(AWK_TEST),Pass)
	$(call __gdk_info,Host awk tool is outdated. Please define HOST_AWK to point to Gawk or Nawk !)
	$(call __gdk_error,Aborting.)
	endif

	#
	# On windows, define the 'cygwin-to-host-path' function here depending on the
	# environment. The rules are the following:
	#
	# 1/ If "cygpath' is not in your path, do not use it at all. It looks like
	# this allows to build with the GDK from MSys without problems.
	#
	# 2/ Since invoking 'cygpath -m' from GNU Make for each source file is
	# _very_ slow, try to generate a Make function that performs the mapping
	# from cygwin to host paths through simple substitutions.
	#
	# 3/ In case we fail horribly, allow the user to define GDK_USE_CYGPATH to '1'
	# in order to use 'cygpath -m' nonetheless. This is only a backup plan in
	# case our automatic substitution function doesn't work (only likely if you
	# have a very weird cygwin setup).
	#
	# The function for 2/ is generated by an awk script. It's really a series
	# of nested patsubst calls, that look like:
	#
	# cygwin-to-host-path = $(patsubst /cygdrive/c/%,c:/%,\
	# $(patsusbt /cygdrive/d/%,d:/%, \
	# $1)
	#
	# except that the actual definition is built from the list of mounted
	# drives as reported by "mount" and deals with drive letter cases (i.e.
	# '/cygdrive/c' and '/cygdrive/C')
	#
	ifeq ($(HOST_OS),windows)
	CYGPATH := $(strip $(HOST_CYGPATH))
	ifndef CYGPATH
	$(call gdk_log, Probing for 'cygpath' program)
	CYGPATH := $(strip $(shell which cygpath 2>/dev/null))
	ifndef CYGPATH
	$(call gdk_log, 'cygpath' was not found in your path)
	else
	$(call gdk_log, 'cygpath' found as: $(CYGPATH))
	endif
	endif
	ifndef CYGPATH
	cygwin-to-host-path = $1
	else
	ifeq ($(GDK_USE_CYGPATH),1)
	$(call gdk_log, Forced usage of 'cygpath -m' through GDK_USE_CYGPATH=1)
	cygwin-to-host-path = $(strip $(shell $(CYGPATH) -m $1))
	else
	# Call an awk script to generate a Makefile fragment used to define a function
	WINDOWS_HOST_PATH_FRAGMENT := $(shell mount \| $(HOST_AWK) -f $(BUILD_AWK)/gen-windows-host-path.awk)
	ifeq ($(GDK_LOG),1)
	$(info Using cygwin substitution rules:)
	$(eval $(shell mount \| $(HOST_AWK) -f $(BUILD_AWK)/gen-windows-host-path.awk -vVERBOSE=1))
	endif
	$(eval cygwin-to-host-path = $(WINDOWS_HOST_PATH_FRAGMENT))
	endif
	endif
	endif # HOST_OS == windows

	# The location of the build system files
	BUILD_SYSTEM := $(GDK_ROOT)/build/core

	# Include common definitions
	include $(BUILD_SYSTEM)/definitions.mk

	# ====================================================================
	#
	# Read all toolchain-specific configuration files.
	#
	# Each toolchain must have a corresponding config.mk file located
	# in build/toolchains/<name>/ that will be included here.
	#
	# Each one of these files should define the following variables:
	# TOOLCHAIN_NAME toolchain name (e.g. arm-eabi-4.2.1)
	# TOOLCHAIN_ABIS list of target ABIs supported by the toolchain.
	#
	# Then, it should include $(ADD_TOOLCHAIN) which will perform
	# book-keeping for the build system.
	#
	# ====================================================================

	# the build script to include in each toolchain config.mk
	ADD_TOOLCHAIN := $(BUILD_SYSTEM)/add-toolchain.mk

	# the list of all toolchains in this GDK
	GDK_ALL_TOOLCHAINS :=
	GDK_ALL_ABIS :=

	TOOLCHAIN_CONFIGS := $(wildcard $(GDK_ROOT)/toolchains/*/config.mk)
	$(foreach _config_mk,$(TOOLCHAIN_CONFIGS),\
	$(eval include $(BUILD_SYSTEM)/add-toolchain.mk)\
	)

	GDK_ALL_TOOLCHAINS := $(call remove-duplicates,$(GDK_ALL_TOOLCHAINS))
	GDK_ALL_ABIS := $(call remove-duplicates,$(GDK_ALL_ABIS))

	# The default toolchain is now arm-eabi-4.4.0, however its
	# C++ compiler is a tad bit more pedantic with certain
	# constructs (e.g. templates) so allow users to switch back
	# to the old 4.2.1 instead if they really want to.
	#
	# NOTE: you won't get armeabi-v7a support though !
	#
	GDK_TOOLCHAIN := $(strip $(GDK_TOOLCHAIN))
	ifdef GDK_TOOLCHAIN
	# check that the toolchain name is supported
	$(if $(filter-out $(GDK_ALL_TOOLCHAINS),$(GDK_TOOLCHAIN)),\
	$(call __gdk_info,GDK_TOOLCHAIN is defined to the unsupported value $(GDK_TOOLCHAIN)) \
	$(call __gdk_info,Please use one of the following values: $(GDK_ALL_TOOLCHAINS))\
	$(call __gdk_error,Aborting)\
	,)
	$(call gdk_log, Using specific toolchain $(GDK_TOOLCHAIN))
	endif

	$(call gdk_log, This GDK supports the following toolchains and target ABIs:)
	$(foreach tc,$(GDK_ALL_TOOLCHAINS),\
	$(call gdk_log, $(space)$(space)$(tc): $(GDK_TOOLCHAIN.$(tc).abis))\
	)

	# ====================================================================
	#
	# Read all platform-specific configuration files.
	#
	# Each platform must be located in build/platforms/android-<apilevel>
	# where <apilevel> corresponds to an API level number, with:
	# 3 -> Android 1.5
	# 4 -> next platform release
	#
	# ====================================================================

	# The platform files were moved in the Android source tree from
	# $TOP/gdk/build/platforms to $TOP/development/gdk/platforms. However,
	# the official GDK release packages still place them under the old
	# location for now, so deal with this here
	#
	GDK_PLATFORMS_ROOT := $(strip $(GDK_PLATFORMS_ROOT))
	ifndef GDK_PLATFORMS_ROOT
	GDK_PLATFORMS_ROOT := $(strip $(wildcard $(GDK_ROOT)/platforms))
	ifndef GDK_PLATFORMS_ROOT
	GDK_PLATFORMS_ROOT := $(strip $(wildcard $(GDK_ROOT)/build/platforms))
	endif

	ifndef GDK_PLATFORMS_ROOT
	$(call __gdk_info,Could not find platform files (headers and libraries))
	$(if $(strip $(wildcard $(GDK_ROOT)/RELEASE.TXT)),\
	$(call __gdk_info,Please define GDK_PLATFORMS_ROOT to point to a valid directory.)\
	,\
	$(call __gdk_info,Please run build/tools/build-platforms.sh to build the corresponding directory.)\
	)
	$(call __gdk_error,Aborting)
	endif

	$(call gdk_log,Found platform root directory: $(GDK_PLATFORMS_ROOT))
	endif
	ifeq ($(strip $(wildcard $(GDK_PLATFORMS_ROOT)/android-*)),)
	$(call __gdk_info,Your GDK_PLATFORMS_ROOT points to an invalid directory)
	$(call __gdk_info,Current value: $(GDK_PLATFORMS_ROOT))
	$(call __gdk_error,Aborting)
	endif

	GDK_ALL_PLATFORMS := $(strip $(notdir $(wildcard $(GDK_PLATFORMS_ROOT)/android-*)))
	$(call gdk_log,Found supported platforms: $(GDK_ALL_PLATFORMS))

	$(foreach _platform,$(GDK_ALL_PLATFORMS),\
	$(eval include $(BUILD_SYSTEM)/add-platform.mk)\
	)