Util lib: use libraries directly instead of header forwarding lib

[hzeller]

Using a public library just to make headers visible is a bazel anti-pattern.

Operations:

# Remove all headers and dependcies on the forwarding library so that it is
# not considered a good candidate for bant dwyu.
buildozer 'remove hdrs' //src/main/cpp/util
buildozer 'remove deps' //src/main/cpp/util

# Add necessary visibility to the libraries to directly depend on
buildozer 'add visibility //src/test/cpp/util:__pkg__' //src/main/cpp/util:numbers
buildozer 'add visibility //src/test/cpp/util:__pkg__' //src/main/cpp/util:port

buildozer 'add visibility //src/main/cpp:__subpackages__' //src/main/cpp/util:filesystem
buildozer 'add visibility //src/main/cpp:__subpackages__' //src/main/cpp/util:md5
buildozer 'add visibility //src/main/cpp:__subpackages__' //src/main/cpp/util:numbers

# Fix all dependencies, but narrow to affected targtes with cpp/util in their path)
. <(bant dwyu ... -g cpp/util)

# Now, we can remove the dependency on the old util library.
buildozer 'remove deps //src/main/cpp/util' $(bant list-targets ... -g cc_ -c3)

# Now that it is not referenced anymore, it can be removed.
buildozer delete //src/main/cpp/util

[hzeller]

Alright, had to rebase as some BUILD files changed in the meantime.

[hzeller]

what is the status here, anything else needed ?

[hzeller]

mmh, so what is the copybara situation ? Can't see it ...