main/libvncserver: fix CVE-2019-15681

ref #10924
7 jobs for !1009 with libvncserver in 1 minute and 34 seconds (queued for 1 second)
detached
Status Job ID Name Coverage
  Lint
passed #10797
docker-alpine x86_64
lint

00:00:23

 
  Build
passed #10802
docker-alpine ci-build aarch64
build-aarch64

00:00:50

passed #10803
docker-alpine ci-build armv7
build-armv7

00:00:57

passed #10801
docker-alpine ci-build ppc64le
build-ppc64le

00:01:08

passed #10800
docker-alpine ci-build s390x
build-s390x

00:01:08

passed #10799
docker-alpine ci-build x86
build-x86

00:00:52

passed #10798
docker-alpine ci-build x86_64
build-x86_64

00:00:47