some ICU constants, macros, etc., especially enum's for UErrorCode and in
uchar.h, do not follow the naming conventions. therefore, they can collide with
other source code's names more easily than necessary.
i will change those names. mostly, they will be prepended with "U_".
this is painful - it breaks a lot of code.
however, we feel that in the interest of a nonambiguous namespace we need to do
this and should have done it when we ported those constants from java or c++
(where class names took care of the namespace issues).