[CMake] fixup_bundle() and stripping prerequisites

[Crni Gorac]

Have CPack setup working great on my Qt-based project - fixup_bundle()
is able to find all required Qt libraries, together with needed
plugins, and include them into installer.  However, these libraries
and plugin files are not stripped, so the resulting installer file is
rather large, and I'd really like to trim its size.  I can understand
that "set(CPACK_STRIP_FILES TRUE)" is working only on the targets in
my program, but I'm wondering - is there any way to have
fixup_bundle() to strip prerequisites?

Thanks.