https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91694
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> --- (In reply to Rishi Khan from comment #4) > (In reply to Jakub Jelinek from comment #3) > > Can you start by saying what OS this is on? The lib*/configure* in gcc tree > > can't use linking in all cases due to newlib startup setups, but it is true > > that in libgomp's configure AC_LINK_IFELSE is used already for most targets > > (but not all). > > This is on my custom OS that doesn't have gethostname ('hcos', which is in > the config.sub upstream). I am actually using newlib. > > It seems like libgomp's configure.ac is already using AC_LINK_IFELSE for all > OS's around line 241 to 'Check for pthread_{,attr_}[sg]etaffinity_np.'. True, but that is something most of the targets don't have, it is glibc specific mostly, so doesn't matter if it fails. > In my newlib startup setup, I only build libgomp in stage2. > See here for Makefile: > https://github.com/riscv/riscv-gnu-toolchain/blob/master/Makefile.in > On line 541 I have --enable-threads and on line 551 I have --enable-libgomp Your OS isn't among those where libgomp is supported. Do you say you have POSIX threads but not gethostname?