Bug#962040: boost1.67: Can not (and should not) fulfill the build dependencies

[Adrian Bunk]

Source: boost1.67
Version: 1.67.0-18
Severity: serious
Tags: ftbfs

The following packages have unmet dependencies:
 builddeps:boost1.67 : Depends: libicu-dev (< 64) but 67.1-2 is to be installed

This is intentional, see #960623 for background.