https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70624
--- Comment #7 from Jack Howarth <howarth.at.gcc at gmail dot com> ---
Also, note that upstream has in compiler-rt/cmake/config-ix.cmake...
if(SANITIZER_MIN_OSX_VERSION VERSION_LESS "10.7")
message(FATAL_ERROR "Too old OS X version: ${SANITIZER_MIN_OSX_VERSION}")
endif()
so they haven't allowed building on 10.6 since
https://github.com/llvm-mirror/compiler-rt/commit/19c8451a0e798abcfd1762fa8196f22b43018d2e#diff-2eeb0237a3e7842df96b4c1280614125
