#5 OS/400 compatibility patch 2 of 3

[Samuel Matzek]

Addded an isOS400 method to Util.java. This method is
called from tcl.lang.ExecCmd in the 3 of 3 patch.

final static boolean
isOS400() {
String os = System.getProperty("os.name");
if (os.equals("OS/400")) {
return true;
}
return false;
}

This patch has been tested on OS/400 v4r4, v4r5, and
an early version of v5r1.

[Samuel Matzek]

Patched Util.java