testing/paho-mqtt-c: upgrade to 1.3.9

 - Switch to cmake.
8 jobs for !29573 with paho-mqtt-c in 2 minutes and 3 seconds (queued for 3 seconds)
latest detached
Status Name Job ID Coverage
  Lint
passed lint #594385
docker-alpine x86_64

00:00:29

 
  Build
passed build-aarch64 #594390
docker-alpine ci-build aarch64

00:00:43

passed build-armhf #594392
docker-alpine ci-build armhf

00:00:42

passed build-armv7 #594391
docker-alpine ci-build armv7

00:00:40

passed build-ppc64le #594389
docker-alpine ci-build ppc64le

00:01:33

passed build-s390x #594388
docker-alpine ci-build s390x

00:00:35

passed build-x86 #594387
docker-alpine ci-build x86

00:00:31

passed build-x86_64 #594386
docker-alpine ci-build x86_64

00:00:27