FindOpenSSL: add target OpenSSL::applink to support OpenSSL's applink feature

Fixes: #20701
7 jobs for !4737 with master in 7 minutes and 13 seconds
detached
Status Name Job ID Coverage
  Build
passed build:debian10-iwyu #4949473
build docker linux

00:01:47

failed build:fedora31-sphinx #4949479
linux-3.17 linux docker build

00:05:18

passed build:fedora31-tidy #4949474
build docker linux

00:01:54

failed build:fedora31-sphinx #4949475
build docker linux linux-3.17

00:03:14

 
  External
passed cdash

passed ghostflow-check-master

passed cdash

 
Name Stage Failure
failed
build:fedora31-sphinx Build
   Uploaded: /builds/gitlab-kitware-cmake ci/Utilities/Sphinx/build/Testing/20200513-0218/Build.xml
Submission successful
CMake Error at /builds/gitlab-kitware-cmake ci/.gitlab/ci/ctest_build.cmake:28 (message):
Found 1 warnings (treating as fatal).


Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1