This is buildroot git HEAD as of today, with glibc 2.21 and gcc-4.8. make[5]: Entering directory '/home/jenkins_slave/buildroot-sparc-buildroot-linux-gnu/output/build/libglib2-2.42.2/glib' CCLD gtester ./.libs/libglib-2.0.so: undefined reference to `__atomic_compare_exchange_4' collect2: error: ld returned 1 exit status Makefile:1446: recipe for target 'gtester' failed make[5]: *** [gtester] Error 1
Fixed by http://git.buildroot.net/buildroot/commit/package/libglib2?id=e4a707e79838680984cd4bb25b5a9959fc44ddc8.