John Hubbard
3ffe806715
BugLink: https://bugs.launchpad.net/bugs/2078304 [ Upstream commit cb708ab9f584f159798b60853edcf0c8b67ce295 ] It's slightly better to set _GNU_SOURCE in the source code, but if one must do it via the compiler invocation, then the best way to do so is this: $(CC) -D_GNU_SOURCE= ...because otherwise, if this form is used: $(CC) -D_GNU_SOURCE ...then that leads the compiler to set a value, as if you had passed in: $(CC) -D_GNU_SOURCE=1 That, in turn, leads to warnings under both gcc and clang, like this: futex_requeue_pi.c:20: warning: "_GNU_SOURCE" redefined Fix this by using the "-D_GNU_SOURCE=" form. Reviewed-by: Edward Liaw <edliaw@google.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Portia Stephens <portia.stephens@canonical.com> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>