cmake HAVE_GNU_TLS examples

oscarlab/betrfs cmake_modules/TokuFeatureDetection.cmake :133 

check_c_source_compiles("#include <pthread.h>
static __thread int tlsvar = 0;
int main(void) { return tlsvar; }" HAVE_GNU_TLS)

alibaba/AliSQL storage/tokudb/ft-index/cmake_modules/TokuFeatureDetection.cmake :128 

check_c_source_compiles("#include <pthread.h>
static __thread int tlsvar = 0;
int main(void) { return tlsvar; }" HAVE_GNU_TLS)

percona/PerconaFT cmake_modules/TokuFeatureDetection.cmake :132 

check_c_source_compiles("#include <pthread.h>
static __thread int tlsvar = 0;
int main(void) { return tlsvar; }" HAVE_GNU_TLS)