Free text input type with validation using a custon supplied class.
This enable very coplext validation, for example, a class could be written
to validate a port number enterd by a user that tries to open a socket
on the port and returns false to the validate method if the socket is in use.
If the osSpecific flag is set the OS of the current system will
be appended to the name of the target actually by ant run so that different
Targets can be run according to the target platform.
This feature goes against the principles of
building cross platform installers, but is provided so that common installer
tasks such as creating icons and shortcuts can be run on Windows for
all those useless users who can't run a command script ;)
Currently there are two modes strict and not strict (lax).
Strict target will return the target name plus the exact String in the
System Property "os.name" this means you will have to provide targets for
every possible OS version.