some icu4c fallout

Hi,

it looks like the recent update of icu4c breaks a couple of other
ports (editors/libreoffice, www/webkitgtk4, x11/qt5/qtwebkit,
x11/qt5/qtwebengine, textproc/libical so far for my build). The
reason appears to be that icu4c used to #define TRUE and FALSE but
no lonber does, and the consuming ports relied on TRUE and FALSE.

TRUE and FALSE are #defined in include/unicode/umachine.h from icu4c,
but are now shielded by an

#if U_DEFINE_FALSE_AND_TRUE || defined(U_IN_DOXYGEN)
...