...found 9 targets...
...updating 4 targets...
gcc.compile.c++ libs/config/checks/architecture/bin/gcc-7.4.0/debug/32.o
...updated 4 targets...
...found 2 targets...
...updating 1 target...
gcc.compile.c++ libs/config/checks/architecture/bin/gcc-7.4.0/debug/arm.o
...updated 1 target...
...patience...
...found 224 targets...
...updating 10 targets...
gcc.compile.c++ bin.v2/libs/thread/build/gcc-7.4.0/debug/threading-multi/visibility-hidden/has_atomic_flag_lockfree_test.o
In file included from /home/buildroot/autobuild/instance-2/output-1/host/opt/ext-toolchain/arm-buildroot-linux-uclibcgnueabihf/include/c++/7.4.0/arm-buildroot-linux-uclibcgnueabihf/bits/os_defines.h:39:0,
                 from /home/buildroot/autobuild/instance-2/output-1/host/opt/ext-toolchain/arm-buildroot-linux-uclibcgnueabihf/include/c++/7.4.0/arm-buildroot-linux-uclibcgnueabihf/bits/c++config.h:533,
                 from /home/buildroot/autobuild/instance-2/output-1/host/opt/ext-toolchain/arm-buildroot-linux-uclibcgnueabihf/include/c++/7.4.0/cstddef:49,
                 from ./boost/config/compiler/gcc.hpp:165,
                 from ./boost/config.hpp:39,
                 from ./boost/atomic/detail/config.hpp:18,
                 from ./boost/atomic/capabilities.hpp:17,
                 from ./boost/atomic/atomic.hpp:19,
                 from libs/thread/src/../build/../../../boost/atomic.hpp:12,
                 from libs/thread/src/../build/has_atomic_flag_lockfree_test.cpp:6:
/home/buildroot/autobuild/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabihf/sysroot/usr/include/features.h:218:5: warning: #warning requested reentrant code, but thread support was disabled [-Wcpp]
 #   warning requested reentrant code, but thread support was disabled
     ^~~~~~~
gcc.link bin.v2/libs/thread/build/gcc-7.4.0/debug/threading-multi/visibility-hidden/has_atomic_flag_lockfree
/home/buildroot/autobuild/instance-2/output-1/host/opt/ext-toolchain/bin/../lib/gcc/arm-buildroot-linux-uclibcgnueabihf/7.4.0/../../../../arm-buildroot-linux-uclibcgnueabihf/bin/ld: cannot find -lpthread
collect2: error: ld returned 1 exit status

    "/home/buildroot/autobuild/instance-2/output-1/host/bin/arm-linux-g++"    -o "bin.v2/libs/thread/build/gcc-7.4.0/debug/threading-multi/visibility-hidden/has_atomic_flag_lockfree" -Wl,--start-group "bin.v2/libs/thread/build/gcc-7.4.0/debug/threading-multi/visibility-hidden/has_atomic_flag_lockfree_test.o"  -Wl,-Bstatic  -Wl,-Bdynamic -lrt -Wl,--end-group -fPIC -pthread -g -fvisibility=hidden -fvisibility-inlines-hidden  

...failed gcc.link bin.v2/libs/thread/build/gcc-7.4.0/debug/threading-multi/visibility-hidden/has_atomic_flag_lockfree...
...failed updating 1 target...
...updated 9 targets...
...found 1 target...
...updating 1 target...
config-cache.write bin.v2/project-cache.jam
...updated 1 target...