toolchain/helpers.mk: strengthen uClibc locale check

Currently, when verifying the configuration of a uClibc toolchain for
the presence of locale support, we check __UCLIBC_HAS_LOCALE__. It
turns out that we in fact also expect __UCLIBC_HAS_XLOCALE__ to be
defined, as without it locale_t is not defined, causing build failure
in some packages, such as libcpprestsdk:

In file included from /home/thomas/autobuild/instance-0/output-1/build/libcpprestsdk-2.10.18/Release/include/cpprest/json.h:18,
                 from /home/thomas/autobuild/instance-0/output-1/build/libcpprestsdk-2.10.18/Release/src/pch/stdafx.h:88,
                 from /home/thomas/autobuild/instance-0/output-1/build/libcpprestsdk-2.10.18/Release/src/http/client/http_client_msg.cpp:13:
/home/thomas/autobuild/instance-0/output-1/build/libcpprestsdk-2.10.18/Release/include/cpprest/asyncrt_utils.h:317:13: error: 'locale_t' does not name a type
  317 |     typedef locale_t xplat_locale;
      |             ^~~~~~~~

As essentially our requirement for uClibc in external toolchains is
"it should match the uClibc configuration used by Buildroot for
internal toolchains", it makes sense to verify
__UCLIBC_HAS_XLOCALE__. Note that of course checking
__UCLIBC_HAS_XLOCALE__ is sufficient, as it cannot be enabled if
__UCLIBC_HAS_LOCALE isn't.

This addresses an issue with the Synopsys ARC external toolchain,
which is built with __UCLIBC_HAS_LOCALE__, but without
__UCLIBC_HAS_XLOCALE__ causing a build failure with some
packages (such as libcpprestsdk).

Therefore, this patch also changes how the Synospys ARC external
toolchain is exposed in Buildroot: it no longer advertise locale
support.

Fixes:

  http://autobuild.buildroot.org/results/e6778e60cc1ea455f5b4511d5824f04d8040f67b

Signed-off-by: Fabrice Fontaine <[email protected]>
Signed-off-by: Thomas Petazzoni <[email protected]>

toolchain/helpers.mk

@@ -307,7 +307,7 @@ check_uclibc = \
 	$(call check_uclibc_feature,__UCLIBC_HAS_LFS__,,$${UCLIBC_CONFIG_FILE},Large file support) ;\
 	$(call check_uclibc_feature,__UCLIBC_HAS_IPV6__,,$${UCLIBC_CONFIG_FILE},IPv6 support) ;\
 	$(call check_uclibc_feature,__UCLIBC_HAS_RPC__,BR2_TOOLCHAIN_HAS_NATIVE_RPC,$${UCLIBC_CONFIG_FILE},RPC support) ;\
-	$(call check_uclibc_feature,__UCLIBC_HAS_LOCALE__,BR2_ENABLE_LOCALE,$${UCLIBC_CONFIG_FILE},Locale support) ;\
+	$(call check_uclibc_feature,__UCLIBC_HAS_XLOCALE__,BR2_ENABLE_LOCALE,$${UCLIBC_CONFIG_FILE},Locale support) ;\
 	$(call check_uclibc_feature,__UCLIBC_HAS_WCHAR__,BR2_USE_WCHAR,$${UCLIBC_CONFIG_FILE},Wide char support) ;\
 	$(call check_uclibc_feature,__UCLIBC_HAS_THREADS__,BR2_TOOLCHAIN_HAS_THREADS,$${UCLIBC_CONFIG_FILE},Thread support) ;\
 	$(call check_uclibc_feature,__PTHREADS_DEBUG_SUPPORT__,BR2_TOOLCHAIN_HAS_THREADS_DEBUG,$${UCLIBC_CONFIG_FILE},Thread debugging support) ;\

toolchain/toolchain-external/toolchain-external-synopsys-arc/Config.in

@@ -5,7 +5,6 @@ config BR2_TOOLCHAIN_EXTERNAL_SYNOPSYS_ARC
 	depends on !BR2_ARCH_NEEDS_GCC_AT_LEAST_10
 	select BR2_TOOLCHAIN_EXTERNAL_UCLIBC
 	select BR2_INSTALL_LIBSTDCPP
-	select BR2_ENABLE_LOCALE
 	select BR2_USE_WCHAR
 	select BR2_TOOLCHAIN_HAS_THREADS
 	select BR2_TOOLCHAIN_HAS_THREADS_NPTL