package/haproxy: fix build on m68k
When threads are enabled, haproxy expects that pthread_getcpuclockid is
available which is not the case on m68k. Fix this by enabling threads
support only if NPTL is available.
Fixes:
- http://autobuild.buildroot.org/results/52cc4b1fcac2a4fc84ab15ec4c692d2cd9b6d8bd
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>