VS: only add custom command line if it is not empty

32 jobs for vs_improve_custom_command
Status Job ID Name Coverage
  External
passed cdash

passed cmake-dash3win7-windows-debug-vs2015

passed cmake-dash3win7-windows-release-ninja

passed ghostflow-branch-check-master

passed ghostflow-commit-check

passed ghostflow-stager

passed cmake-dash3win7-windows-debug-vs2015

00:44:18

passed cmake-dash3win7-windows-debug-vs2015

passed cmake-dash3win7-windows-debug-vs2015

passed cmake-dash3win7-windows-debug-vs2015

passed cmake-dash3win7-windows-debug-vs2015

passed cmake-dash3win7-windows-release-ninja

passed cmake-dash3win7-windows-release-ninja

passed cmake-dash3win7-windows-release-ninja

passed cmake-dash3win7-windows-release-ninja

passed cmake-dash3win7-windows-release-ninja

00:20:33

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager