Recently, I couldn't build GNU Emacs on a uclibc-ng-1.0.33 system. The issue eventually went to Gnulib; they pushed a workaround but concluded it's a uClibc issue. Their summary, as presented in the patch in the message below: For details, see https://lists.gnu.org/archive/html/bug-gnulib/2020-08/msg00098.html and further down the thread. I was advised to report this to you so here it goes.