Disable compiler supported TLS to avoid deadlocks with dl_close
This patch is an attempt to fix a gimp deadlock with openblas installed: #903514.
This patch disable HAS_COMPILER_TLS which force to use pthreads' TLS. On my machine, this fix the deadlock between TLS and dl_close and makes gimp to start fine. This need to be tested with others who encountered instabilities with gimp when openblas is installed.