今天遇到rn问题：
ld: warning: Could not find or use auto-linked library 'swiftCoreMIDI'
Undefined symbols for architecture x86_64:
"___darwin_check_fd_set_overflow", referenced from:
_RAND_poll in libcrypto.a(rand_unix.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
解决办法:项目里面创建一个空的swift文件，xcode提示：
