[Bug]: I try use it in IOS and got error

### What Operating System(s) are you seeing this problem on?

macOS (Intel)

### dlib version

19.24

### Python version

_No response_

### Compiler

Xcode IOS

### Expected Behavior

_No response_

### Current Behavior

Failed to build iOS app
Could not build the precompiled application for the device.
Error (Xcode): Undefined symbol: dlib::entropy_decoder_kernel_2::get_target(unsigned int)

Error (Xcode): Undefined symbol: dlib::entropy_decoder_kernel_2::set_stream(std::__1::basic_istream >&)

Error (Xcode): Undefined symbol: dlib::entropy_decoder_kernel_2::decode(unsigned int, unsigned int)

Error (Xcode): Undefined symbol: dlib::entropy_decoder_kernel_2::entropy_decoder_kernel_2()

Error (Xcode): Undefined symbol: dlib::entropy_decoder_kernel_2::~entropy_decoder_kernel_2()

Error (Xcode): Undefined symbol: dlib::base64::base64()

Error (Xcode): Undefined symbol: dlib::base64::~base64()

Error (Xcode): Undefined symbol: dlib::base64::decode(std::__1::basic_istream >&, std::__1::basic_ostream >&) const

Error (Xcode): Linker command failed with exit code 1 (use -v to see invocation)

### Steps to Reproduce

Follow https://stackoverflow.com/questions/34591254/how-to-build-dlib-for-ios/35058969#35058969

### Anything else?

_No response_