AC_CHECK_FUNCS() doesn't check declaration, only library symbol. For one, FreeBSD never had pthread_getname_np() but added a similar function in base r337983. See contrib/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc $ cat >a.c char pthread_getname_np(); int main() { pthread_getname_np(); return 0; } $ cc a.c -fsanitize=address $ cc a.c ld: error: undefined symbol: pthread_getname_np >>> referenced by a.c >>> /tmp/a-101e7b.o:(main) cc: error: linker command failed with exit code 1 (use -v to see invocation) $ pkg install python27 $ hash git 2>/dev/null || pkg install mercurial $ hg clone https://hg.mozilla.org/mozilla-unified firefox || git clone https://github.com/mozilla/gecko-dev firefox $ cd firefox $ hg update central || git checkout origin/master $ echo "ac_add_options --with-libclang-path=${LOCALBASE-/usr/local}/llvm80/lib" >>.mozconfig $ echo "ac_add_options --enable-address-sanitizer" >>.mozconfig $ ./mach bootstrap # select Firefox for Desktop $ ./mach build [...] In file included from objdir/js/src/Unified_cpp_js_src9.cpp:29: js/src/threading/posix/Thread.cpp:174:8: error: use of undeclared identifier 'pthread_getname_np'; did you mean 'pthread_get_name_np'? rv = pthread_getname_np(pthread_self(), nameBuffer, len); ^~~~~~~~~~~~~~~~~~ pthread_get_name_np /usr/include/pthread_np.h:52:6: note: 'pthread_get_name_np' declared here void pthread_get_name_np(pthread_t, char *, size_t); ^ In file included from objdir/js/src/Unified_cpp_js_src9.cpp:29: js/src/threading/posix/Thread.cpp:174:8: error: assigning to 'int' from incompatible type 'void' rv = pthread_getname_np(pthread_self(), nameBuffer, len); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2 errors generated.
I suspect it would be simplest to just make pthread_(get|set)name_np() aliases of pthread_(get|set)_name_np(). Linux and NetBSD use the former, FreeBSD and OpenBSD use the latter. We could just teach compiler-rt to intercept pthread_get_name_np(), but it's a silly compatibility wart that will bite over and over I'm sure.
(In reply to Mark Johnston from comment #1) https://reviews.freebsd.org/D25117
A commit references this bug: Author: kib Date: Wed Jun 3 20:54:38 UTC 2020 New revision: 361770 URL: https://svnweb.freebsd.org/changeset/base/361770 Log: Add pthread_getname_np() and pthread_setname_np() aliases for pthread_get_name_np() and pthread_set_name_np(), to be compatible with Linux. PR: 238404 Proposed and reviewed by: markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D25117 Changes: head/include/pthread_np.h head/lib/libthr/pthread.map head/lib/libthr/thread/thr_info.c head/share/man/man3/Makefile head/share/man/man3/pthread_set_name_np.3