Fix compile errors on case-sensitive APFS

[ledyba-z]

Hi. I couldn't add protobuf to iOS App. using CocoaPods with compile errors:

I figured out Any.pbobjc.h is located on Protobuf, not protobuf, and also, my disk is formatted as case-sensitive APFS. So that the objc compiler cannot find the header.

Here is my podfile:

# Uncomment this line to define a global platform for your project
platform :ios, '11.0'
use_modular_headers!
inhibit_all_warnings!
# use_frameworks!

target '*****' do
    ....
    pod 'Protobuf'
    ....
end

This patch may also fixes: invertase/react-native-firebase#2780

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[ledyba-z]

@googlebot I signed it!

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[ledyba-z]

Oh, I found these closed pull requests...

Override CocoaPods module to lowercase by paulb777 · Pull Request #6464 · protocolbuffers/protobuf
#6464

Fix CocoaPods case warnings by paulb777 · Pull Request #6190 · protocolbuffers/protobuf
#6190

What should I do for this compile error?

I know that this patch solves my compile errors, but is this the correct way?
To be honest, I am not familiar with cocoapods/iOS/ObjC.

---

I'm using Xcode Version 11.3 (11C29),

other software versions:

% cat .ruby-version
2.6.3
% bundler exec pod --version
1.8.4

[thomasvl]

As you see from those other issues, there isn't a clear "fix" at the moment.

This PR would cause warnings for some of the other setups because the tree of directories/links created by cocoapods isn't consistent (some times it is the package name, some times it is the module name).

So short of doing what is suggested in some of those where we abandon the Protobuf pod name for protobuf and thus require everyone to migrate, there doesn't seem to be a real solution (and during that migration folks could run into double definitions when they get both).

[thomasvl]

ps - #6803 is the currently open issue for tracking the problem

[ledyba-z]

Thank you reviewing and telling me the current status!
OK, I will track that issue.