summaryrefslogtreecommitdiffstats
path: root/toolchain/toolchain-crosstool-ng/crosstool-ng.mk
blob: ec6e1889b020b825fff50ad415b290b279269afe (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
# Makefile fragment for building toolchain with crosstool-NG

# As a reference, you can look at toolchain/toolchain-external/ext-tool.mk
# for a generic approach to external toolchains.
# crosstool-NG as a backend is but a kind of external toolchains,
# except that it is not pre-built.

#-----------------------------------------------------------------------------
# Internal variables

CTNG_DIR := $(BUILD_DIR)/build-toolchain

CTNG_UCLIBC_CONFIG_FILE := $(TOPDIR)/toolchain/toolchain-crosstool-ng/uClibc.config
CTNG_CONFIG_FILE:=$(call qstrip,$(BR2_TOOLCHAIN_CTNG_CONFIG))

# Hack! ct-ng is in fact a Makefile script. As such, it accepts all
# make options, such as -C, which makes it uneeded to chdir prior
# to calling ct-ng.
# $1: the set of arguments to pass to ct-ng
define ctng
PATH=$(HOST_PATH) ct-ng -C $(CTNG_DIR) --no-print-directory $(1)
endef

#-----------------------------------------------------------------------------
# 'uclibc' is the target to depend on to get the toolchain and prepare
# the staging directory and co.
uclibc: dependencies $(STAMP_DIR)/ct-ng-toolchain-installed

# 'uclibc-source' is the target used by the infra structure to mean
# "we just want to download the toolchain's sources, not build it"
# For crosstool-NG, we need it to be configured before we can download;
# then we have to override a config option to just do the download
uclibc-source: $(CTNG_DIR)/.config
	$(Q)$(call ctng,build CT_ONLY_DOWNLOAD=y)

#-----------------------------------------------------------------------------
# Installing the libs to target/ and staging/

#--------------
# The generic system libraries (in /lib)
CTNG_LIBS_LIB := ld*.so libc.so libcrypt.so libdl.so libgcc_s.so libm.so    \
                 libnsl.so libpthread.so libresolv.so librt.so libutil.so

#--------------
# The libc-specific system libraries (in /lib)
# Note: it may be needed to tweak the NSS libs in the glibc and eglibc cases...
CTNG_LIBS_uClibc :=
CTNG_LIBS_glibc  := libnss_files.so libnss_dns.so
CTNG_LIBS_eglibc := $(CTNG_LIBS_glibc)

#--------------
# All that we need in /lib
CTNG_LIBS_LIB += $(CTNG_LIBS_$(call qstrip,$(BR2_TOOLCHAIN_CTNG_LIBC)))

#--------------
# All that we need in /usr/lib
ifneq ($(BR2_INSTALL_LIBSTDCPP),)
CTNG_LIBS_USR_LIB += libstdc++.so
endif

#--------------
# Actual copy
$(STAMP_DIR)/ct-ng-toolchain-installed: $(STAMP_DIR)/ct-ng-toolchain-built
	$(Q)mkdir -p $(TARGET_DIR)/lib
	$(Q)CTNG_TUPLE="$$( $(call ctng,show-tuple) )";                     \
	    CTNG_SYSROOT="$(HOST_DIR)/usr/$${CTNG_TUPLE}/sysroot";          \
	    echo "CTNG_TUPLE='$${CTNG_TUPLE}'";                             \
	    echo "CTNG_SYSROOT='$${CTNG_SYSROOT}'";                         \
	    echo "Copy external toolchain libraries to target...";          \
	    for libs in $(CTNG_LIBS_LIB); do                                \
	        $(call copy_toolchain_lib_root,$${CTNG_SYSROOT},$$libs,/lib); \
	    done;                                                           \
	    for libs in $(CTNG_LIBS_USR_LIB); do                            \
	        $(call copy_toolchain_lib_root,$${CTNG_SYSROOT},$$libs,/usr/lib); \
	    done;
	$(Q)touch $@

#-----------------------------------------------------------------------------
# Building the toolchain
# Note: $(STAMP_DIR)/ct-ng-toolchain-built can have more dependencies,
#       depending on the selected C library. Those deps are added later

$(STAMP_DIR)/ct-ng-toolchain-built: $(CTNG_DIR)/.config
	$(Q)$(call ctng,build.$(BR2_JLEVEL))
	$(Q)printf "\n"
	$(Q)touch $@

#-----------------------------------------------------------------------------
# Configuring the toolchain

#--------------
# We push BR options down to CT-NG, munging the default configuration
# with sed expressions.
# - first one for non-path options
# - second for path options (because they have no prompt, they
#                            always get set to the default value)
# - third for C library .config (if it has one, eg. uClibc)
CTNG_FIX_DOT_CONFIG_SED       :=
CTNG_FIX_DOT_CONFIG_PATHS_SED :=
CTNG_FIX_DOT_CONFIG_LIBC_SED  :=

#--------------
# A few generic functions

# Munge a config file, given a sed expression
# $1: the .config file to munge
# $2: the sed expression to apply
define ctng-fix-dot-config
	$(Q)sed -r -e '$(2)' $(1) >$(1).sed
	$(Q)cmp $(1) $(1).sed >/dev/null 2>&1 && rm -f $(1).sed || mv -f $(1).sed $(1)
endef

# This function checks the .config did actually change
# If not changed, then current .config will be touched with reference to the
# stamp file. If the configuration did change, nothing is done.
# $1: the current .config to check
# $2: the time-stamped .config file
define ctng-check-config-changed
	$(Q)old_md5="$$( grep -v -E '^(#|$$)' $(2) 2>/dev/null  \
	                 |md5sum                                \
	                 |cut -d ' ' -f 1                       \
	               )";                                      \
	    new_md5="$$( grep -v -E '^(#|$$)' $(1) 2>/dev/null  \
	                 |md5sum                                \
	                 |cut -d ' ' -f 1                       \
	               )";                                      \
	    if [ $${old_md5} = $${new_md5} -a -f $(2) ]; then   \
	        touch -r $(2) $(1);                             \
	    fi
endef

#--------------
# Massage BR2_ARCH so that it matches CT-NG's ARCH
#
# Note: a lot of the following tricks would become unneeded if one day
# buildroot and crosstool-NG had matching options, especially for the
# target description: arch name, bitness, endianness...
#
# Note-2: missing conformity check between BR's .config and libc features.
# Use check_uclibc or check_glibc.

# Defaults:
CTNG_ARCH   := $(CTNG_BR2_ARCH)
CTNG_ENDIAN :=
CTNG_BIT    :=
# Architecture overides, only overide pertinent vars:
ifeq      ($(BR2_arm),y)
CTNG_ARCH   := arm
CTNG_ENDIAN := LE
else ifeq ($(BR2_armeb),y)
CTNG_ARCH   := arm
CTNG_ENDIAN := BE
else ifeq ($(BR2_i386),y)
CTNG_ARCH   := x86
CTNG_BIT    := 32
else ifeq ($(BR2_mips),y)
CTNG_ARCH   := mips
CTNG_ENDIAN := BE
else ifeq ($(BR2_mipsel),y)
CTNG_ARCH   := mips
CTNG_ENDIAN := LE
else ifeq ($(BR2_powerpc),y)
CTNG_ARCH   := powerpc
CTNG_BIT    := 32
else ifeq ($(BR2_x86_64),y)
CTNG_ARCH   := x86
CTNG_BIT    := 64
# Add other architecture overides below:
#  - keep alphabetic order
#  - duplicate next 4 lines, and uncomment
#       else ifeq ($(BR2_<arch_name_here>),y)
#       CTNG_ARCH   :=
#       CTNG_ENDIAN :=
#       CTNG_BIT    :=
#  - remove unneeded vars
#  - add BR arch-name on ifeq line
#  - fill-in required CTNG_* vars
endif

#--------------
# Massage BR options into CTNG .config file
# CT_ARCH                   : handled by the backend mechanism
# CT_ARCH_[BL]E             : endianness
# CT_ARCH_(32|64)           : bitness
# CT_PREFIX_DIR             : install into BR's toolchain dir
# CT_INSTALL_DIR_RO         : do *not* chmod a-w the toolchain dir
# CT_LOCAL_TARBALLS_DIR     : share downloads with BR
# CT_SYSROOT_DIR_PREFIX     : no prefix needed, really
# CT_TARGET_VENDOR          : try to set a unique vendor string, to avoid clashing with BR's vendor string
# CT_TARGET_ALIAS           : set the target tuple alias to REAL_GNU_TARGET_NAME so that packages' ./configure find the compiler
# CT_DEBUG_gdb              : deselect gdb+gdbserver if buildroot builds its own
# CT_CC_LANG_CXX            : required if we copy libstdc++.so, and build C++
# CT_LIBC_UCLIBC_CONFIG_FILE: uClibc config file, if needed
#
# Lots of other awfull sed manipulations go here, to override CT-NG's .config
# with BR2 config options.
# Known missing: arch options, uClibc/eglibc config...
#
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_INSTALL_DIR_RO)=y:\# \1 is not set:;
CTNG_FIX_DOT_CONFIG_SED += s:^(|\# )(CT_ARCH_[BL]E).*:\# \2 is not set:;
CTNG_FIX_DOT_CONFIG_SED += s:^\# (CT_ARCH_$(CTNG_ENDIAN)) is not set:\1=y:;
CTNG_FIX_DOT_CONFIG_SED += s:^(|\# )(CT_ARCH_(32|64)).*:\# \2 is not set:;
CTNG_FIX_DOT_CONFIG_SED += s:^\# (CT_ARCH_$(CTNG_BIT)) is not set:\1=y:;
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_TARGET_VENDOR)=.*:\1="unknown":;
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_TARGET_ALIAS)=.*:\1="$(GNU_TARGET_NAME)":;
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_CC_PKGVERSION)="(.*)":\1="crosstool-NG $(CTNG_VERSION) - buildroot $(BR2_VERSION_FULL)":;
ifneq ($(call qstrip,$(BR2_USE_MMU)),)
CTNG_FIX_DOT_CONFIG_SED += s:^\# (CT_ARCH_USE_MMU) is not set:\1=y:;
else
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_ARCH_USE_MMU)=y:\# \1 is not set:;
endif
ifneq ($(call qstrip,$(BR2_PACKAGE_GDB_SERVER))$(call qstrip,$(BR2_PACKAGE_GDB_HOST)),)
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_DEBUG_gdb)=.*:\# \1 is not set:;
endif
ifeq ($(call qstrip,$(BR2_TOOLCHAIN_CTNG_CXX)),y)
CTNG_FIX_DOT_CONFIG_SED += s:^\# (CT_CC_LANG_CXX) is not set:\1=y:;
else
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_CC_LANG_CXX)=.*:\# \1 is not set:;
endif

# Shoe-horn CPU variant now
ifneq ($(call qstrip,$(BR2_GCC_TARGET_ARCH)),)
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_ARCH_ARCH)=.*:\1=$(BR2_GCC_TARGET_ARCH):;
endif
ifneq ($(call qstrip,$(BR2_GCC_TARGET_TUNE)),)
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_ARCH_TUNE)=.*:\1=$(BR2_GCC_TARGET_TUNE):;
endif

# And floating point now
ifeq ($(call qstrip,$(BR2_SOFT_FLOAT)),)
CTNG_FIX_DOT_CONFIG_SED += s:^\# (CT_ARCH_FLOAT_HW) is not set:\1=y:;
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_ARCH_FLOAT_SW)=y:\# \1 is not set:;
else
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_ARCH_FLOAT_HW)=y:\# \1 is not set:;
CTNG_FIX_DOT_CONFIG_SED += s:^\# (CT_ARCH_FLOAT_SW) is not set:\1=y:;
endif

# Thread implementation selection
CTNG_FIX_DOT_CONFIG_SED += s:^(|\# )(CT_THREADS_NONE).*:\# \2 is not set:;
CTNG_FIX_DOT_CONFIG_SED += s:^(|\# )(CT_THREADS_LINUXTHREADS).*:\# \2 is not set:;
CTNG_FIX_DOT_CONFIG_SED += s:^(|\# )(CT_THREADS_NPTL).*:\# \2 is not set:;
ifneq ($(call qstrip,$(BR2_TOOLCHAIN_CTNG_THREADS_PTHREADS))$(call qstrip,$(BR2_TOOLCHAIN_CTNG_THREADS_PTHREADS_OLD)),)
CTNG_FIX_DOT_CONFIG_SED += s:^(|\# )(CT_THREADS_LINUXTHREADS).*:\2=y:;
 ifneq ($(call qstrip,$(BR2_TOOLCHAIN_CTNG_uClibc)),)
  ifneq ($(call qstrip,$(BR2_TOOLCHAIN_CTNG_THREADS_PTHREADS_OLD)),)
CTNG_FIX_DOT_CONFIG_SED += s:^(|\# )(CT_LIBC_UCLIBC_LNXTHRD_NEW).*:\# \2 is not set:;
CTNG_FIX_DOT_CONFIG_SED += s:^(|\# )(CT_LIBC_UCLIBC_LNXTHRD_OLD).*:\2=y:;
  else
CTNG_FIX_DOT_CONFIG_SED += s:^(|\# )(CT_LIBC_UCLIBC_LNXTHRD_OLD).*:\# \2 is not set:;
CTNG_FIX_DOT_CONFIG_SED += s:^(|\# )(CT_LIBC_UCLIBC_LNXTHRD_NEW).*:\2=y:;
  endif
 endif
else ifneq ($(call qstrip,$(BR2_TOOLCHAIN_CTNG_THREADS_NPTL)),)
CTNG_FIX_DOT_CONFIG_SED += s:^(|\# )(CT_THREADS_NPTL).*:\2=y:;
else ifneq ($(call qstrip,$(BR2_TOOLCHAIN_CTNG_THREADS_NONE)),)
CTNG_FIX_DOT_CONFIG_SED += s:^(|\# )(CT_THREADS_NONE).*:\2=y:;
endif

#--------------
# And the specials for paths
CTNG_FIX_DOT_CONFIG_PATHS_SED += s:^(CT_PREFIX_DIR)=.*:\1="$(HOST_DIR)/usr":;
CTNG_FIX_DOT_CONFIG_PATHS_SED += s:^(CT_LOCAL_TARBALLS_DIR)=.*:\1="$(DL_DIR)":;
CTNG_FIX_DOT_CONFIG_PATHS_SED += s:^(CT_SYSROOT_NAME)=.*:\1="sysroot":;
CTNG_FIX_DOT_CONFIG_PATHS_SED += s:^(CT_SYSROOT_DIR_PREFIX)=.*:\1="":;

#--------------
# uClibc specific options
ifeq ($(BR2_TOOLCHAIN_CTNG_uClibc),y)

# Handle the locales option
ifneq ($(call qstrip,$(BR2_ENABLE_LOCALE)),)
CTNG_FIX_DOT_CONFIG_SED += s:^\# (CT_LIBC_UCLIBC_LOCALES) is not set:\1=y\n\# CT_LIBC_UCLIBC_LOCALES_PREGEN_DATA is not set:;
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_LIBC_UCLIBC_LOCALES_PREGEN_DATA)=.*:\# \1 is not set:;
else
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_LIBC_UCLIBC_LOCALES)=.*:\# \1 is not set:;
endif

# Handle the wide-char option
ifneq ($(call qstrip,$(BR2_USE_WCHAR)),)
CTNG_FIX_DOT_CONFIG_SED += s:^\# (CT_LIBC_UCLIBC_WCHAR) is not set:\1=y:;
else
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_LIBC_UCLIBC_WCHAR)=.*:\# \1 is not set:;
endif

# Handle the LFS option
ifneq ($(call qstrip,$(BR2_LARGEFILE)),)
CTNG_FIX_DOT_CONFIG_LIBC_SED += s:^\# (UCLIBC_HAS_LFS) is not set:\1=y:;
else
CTNG_FIX_DOT_CONFIG_LIBC_SED += s:^(UCLIBC_HAS_LFS)=.*:\# \1 is not set:;
endif

# Handle the IPv6 option
ifneq ($(call qstrip,$(BR2_INET_IPV6)),)
CTNG_FIX_DOT_CONFIG_LIBC_SED += s:^\# (UCLIBC_HAS_IPV6) is not set:\1=y:;
else
CTNG_FIX_DOT_CONFIG_LIBC_SED += s:^(UCLIBC_HAS_IPV6)=.*:\# \1 is not set:;
endif

# Handle the RPC option
ifneq ($(call qstrip,$(BR2_INET_RPC)),)
CTNG_FIX_DOT_CONFIG_LIBC_SED += s:^\# (UCLIBC_HAS_RPC) is not set:\1=y\nUCLIBC_HAS_FULL_RPC=y\nUCLIBC_HAS_REENTRANT_RPC=y:;
CTNG_FIX_DOT_CONFIG_LIBC_SED += s:^\# (UCLIBC_HAS_FULL_RPC) is not set:\1=y:;
CTNG_FIX_DOT_CONFIG_LIBC_SED += s:^\# (UCLIBC_HAS_REENTRANT_RPC) is not set:\1=y:;
else
CTNG_FIX_DOT_CONFIG_LIBC_SED += s:^(UCLIBC_HAS_RPC)=.*:\# \1 is not set:;
endif

# Handle the program_invocation_name option
ifneq ($(call qstrip,$(BR2_PROGRAM_INVOCATION)),)
CTNG_FIX_DOT_CONFIG_LIBC_SED += s:^\# (UCLIBC_HAS_PROGRAM_INVOCATION_NAME) is not set:\1=y:;
else
CTNG_FIX_DOT_CONFIG_LIBC_SED += s:^(UCLIBC_HAS_PROGRAM_INVOCATION_NAME)=y:\# \1 is not set:;
endif

# Instruct CT-NG's .config where to find the uClibc's .config
CTNG_FIX_DOT_CONFIG_PATHS_SED += s:^(CT_LIBC_UCLIBC_CONFIG_FILE)=.*:\1="$(CTNG_DIR)/libc.config":;

# And add this to the toolchain build dependency
$(STAMP_DIR)/ct-ng-toolchain-built: $(CTNG_DIR)/libc.config

# And here is how we get this uClibc's .config
$(CTNG_DIR)/libc.config: $(CTNG_UCLIBC_CONFIG_FILE) $(CONFIG_DIR)/.config
	-$(Q)cp -a $@ $@.timestamp
	$(Q)cp -f $< $@
	$(call ctng-fix-dot-config,$@,$(CTNG_FIX_DOT_CONFIG_LIBC_SED))
	$(call ctng-check-config-changed,$@,$@.timestamp)
	$(Q)rm -f $@.timestamp

endif # LIBC is uClibc

#--------------
# glibc/eglibc specific options
ifeq ($(BR2_TOOLCHAIN_CTNG_glibc)$(BR2_TOOLCHAIN_CTNG_eglibc),y)

# Force unwind support
CTNG_FIX_DOT_CONFIG_SED += s:^\# (CT_LIBC_GLIBC_FORCE_UNWIND) is not set:\1=y:;

# Force non-fortified build
CTNG_FIX_DOT_CONFIG_SED += s:^(CT_LIBC_ENABLE_FORTIFIED_BUILD)=y:\# \1 is not set:;

endif # LIBC is glibc or eglibc

#--------------
# Small functions to shoe-horn the above into crosstool-NG's .config

# Function to update the .config
# We first munge the .config to shoe-horn defaults, then we push that unto
# crosstool-NG's oldconfig process, to sort out wizy-wazy deps, and then we
# shoe-horn paths again, as they get ripped-out by oldconfig (is that a bug
# or a feature of kconfig?)
# $1: the .config file to munge
define ctng-oldconfig
	$(call ctng-fix-dot-config,$(1),$(CTNG_FIX_DOT_CONFIG_SED))
	$(Q)yes ''                                             |\
	$(call ctng,CT_IS_A_BACKEND=y                           \
	            CT_BACKEND_ARCH=$(CTNG_ARCH)                \
	            CT_BACKEND_KERNEL=linux                     \
	            CT_BACKEND_LIBC=$(BR2_TOOLCHAIN_CTNG_LIBC)  \
	            oldconfig                                   )
	$(call ctng-fix-dot-config,$(1),$(CTNG_FIX_DOT_CONFIG_PATHS_SED))
endef

# We need the host crosstool-NG before we can even begin working
# on the toolchain. Using order-only dependency, as we do not want
# to rebuild the toolchain for every run...
$(CTNG_DIR)/.config: | host-crosstool-ng

# Default configuration
# Depends on top-level .config because it has options we have to shoe-horn
# into crosstool-NG's .config
# Only copy the original .config file if we don't have one already.
# Check that given config file matches selected C library.
# We need to call oldconfig twice in a row to ensure the options
# are correctly set ( eg. if an option is new, then the initial sed
# can't do anything about it ) Ideally, this should go in oldconfig
# itself, but it's much easier to handle here.

$(CTNG_DIR)/.config: $(CTNG_CONFIG_FILE) $(CONFIG_DIR)/.config
	$(Q)if [ ! -f $@ ]; then                                                        \
	        mkdir -p "$(CTNG_DIR)";                                                 \
	        libc="$$(awk -F '"' '$$1=="CT_LIBC=" { print $$2; }' "$<")";            \
	        if [ "$${libc}" != "$(BR2_TOOLCHAIN_CTNG_LIBC)" ]; then                 \
	            echo "* Inconsistency in crosstool-NG config file '$<'";            \
	            echo "* - buildroot configured for '$(BR2_TOOLCHAIN_CTNG_LIBC)'";   \
	            echo "* - given config file for '$${libc}'";                        \
	            exit 1;                                                             \
	        fi;                                                                     \
	        cp -f $< $@;                                                            \
	    fi
	$(Q)cp -a $@ $@.timestamp
	$(call ctng-oldconfig,$@)
	$(call ctng-oldconfig,$@)
	$(call ctng-check-config-changed,$@,$@.timestamp)
	$(Q)rm -f $@.timestamp

# Manual configuration
ctng-menuconfig: $(CTNG_DIR)/.config
	$(Q)cp -a $< $<.timestamp
	$(Q)$(call ctng,CT_IS_A_BACKEND=y                           \
	                CT_BACKEND_ARCH=$(CTNG_ARCH)                \
	                CT_BACKEND_KERNEL=linux                     \
	                CT_BACKEND_LIBC=$(BR2_TOOLCHAIN_CTNG_LIBC)  \
	                menuconfig                                  )
	$(call ctng-oldconfig,$<)
	$(call ctng-check-config-changed,$<,$<.timestamp)
	$(Q)rm -f $<.timestamp