Mac: Additional dw_exec() code to locate the full path to application URLs. On Catalina and later dw_exec() now supports specifying the program by application bundle identifier, in addition to the application name. Check if the selectors are available and call them directly to support their eventual removal and to avoid deprecation warnings.

[Desktop Entry]
Name=Dynamic Windows Test
Exec=@prefix@/bin/dwtest 
Terminal=false
MultipleArgs=false
Type=Application
Categories=Application;Development;X-Red-Hat-Base;