Steps to reproduce:
1. Open the attached project
2. Build to iOS
3. In Xcode, build to an iOS device

Result:
[iOS]
Build fails with linker error:
Showing All Messages
Undefined symbols for architecture arm64:
"RegisterClass_BlendTree()", referenced from:
RegisterAllClasses() in UnityClassRegistration.o
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

[Android]
Editor crashes, Editor log indicates a compiler error:
The process has forked and you cannot use this CoreFoundation functionality safely. You MUST exec().
Break on __THE_PROCESS_HAS_FORKED_AND_YOU_CANNOT_USE_THIS_COREFOUNDATION_FUNCTIONALITY___YOU_MUST_EXEC__() to debug.

Reproduced on: 5.3.8f1, 5.4.6f2
Did not reproduce on: 5.5.4p2, 2017.1.0p5