While this code is used by us if the program couldn't be launched at all, it doesn't mean that it didn't run as -1 could also be returned by the child process to indicate an error after outputting something, so we should still read its output in this case. Closes #15205. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74352 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775