cmake HAVE_BACKTRACE_WITH_EXECINFO examples

oscarlab/betrfs cmake_modules/TokuFeatureDetection.cmake :96 

check_function_exists(backtrace HAVE_BACKTRACE_WITH_EXECINFO)

alibaba/AliSQL storage/tokudb/ft-index/cmake_modules/TokuFeatureDetection.cmake :91 

check_function_exists(backtrace HAVE_BACKTRACE_WITH_EXECINFO)

percona/PerconaFT cmake_modules/TokuFeatureDetection.cmake :92 

check_function_exists(backtrace HAVE_BACKTRACE_WITH_EXECINFO)