Hi Bruno, It looks like it is time for me to start learning m4.
When running ./configure in findutils I see this warning: checking for pthread.h... yes ... ./configure: line 31218: test: =: unary operator expected checking for pthread_spin_init... yes checking for pthread_t... yes checking for pthread_spinlock_t... yes Line 31218 is the first line in this block. I believe it is because $HAVE_PTHREAD_H expands to nothing: if test $HAVE_PTHREAD_H = 0 || test $HAVE_PTHREAD_SPINLOCK_T = 0; then HAVE_PTHREAD_SPIN_INIT=0 HAVE_PTHREAD_SPIN_LOCK=0 HAVE_PTHREAD_SPIN_TRYLOCK=0 HAVE_PTHREAD_SPIN_UNLOCK=0 HAVE_PTHREAD_SPIN_DESTROY=0 else $ grep -n 'HAVE_PTHREAD_H' configure 810:HAVE_PTHREAD_H 5111:as_fn_append ac_header_c_list " pthread.h pthread_h HAVE_PTHREAD_H" 31218: if test $HAVE_PTHREAD_H = 0 || test $HAVE_PTHREAD_SPINLOCK_T = 0; then 31368: HAVE_PTHREAD_H=1 31373: HAVE_PTHREAD_H=0 31377: HAVE_PTHREAD_H=0 31382: #if HAVE_PTHREAD_H 31394: #if HAVE_PTHREAD_H 59474: if test $HAVE_PTHREAD_H = 0; then It looks like maybe it is due to this? commit 4851abd89ce1ed641cc5d601f8764af23f987182 Author: Bruno Haible <br...@clisp.org> Date: Thu Mar 28 22:05:39 2024 +0100 pthread-h: Fix override of pthread_spinlock_t with non-GNU compilers. * m4/pthread-spin.m4 (gl_PTHREAD_SPIN): Define through AC_DEFUN_ONCE. Require gl_PTHREAD_H_DEFAULTS, not gl_PTHREAD_H. Collin