-pthread is indeed sufficient when it's really given to the linking $CC run. > Does someone know why this is going wrong? In unbound.spec I see: %{__make} CFLAGS="$RPM_OPT_FLAGS -D_GNU_SOURCE" QUIET=no %{?_smp_mflags} This overrides the CFLAGS setting written into Makefile by configure. You should never override CFLAGS in this way. The place to set CFLAGS is in the configure line. You use %configure, which uses CFLAGS="${CFLAGS:-%optflags}". (%optflags is the same as $RPM_OPT_FLAGS.) So what would work is: %configure ... \ CFLAGS="$RPM_OPT_FLAGS -D_GNU_SOURCE" However, what I would really suggest is that you instead put -D_GNU_SOURCE into CFLAGS in the source package itself. If you need that, it should not be a Fedora-specific issue. e.g., early in configure.ac you can use: CFLAGS="$CFLAGS -D_GNU_SOURCE" Thanks, Roland -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel