libc/src/__support/big_int.h has the header guards: ```c #ifndef LLVM_LIBC_SRC___SUPPORT_UINT_H #define LLVM_LIBC_SRC___SUPPORT_UINT_H ... #endif // LLVM_LIBC_SRC___SUPPORT_UINT_H ``` These 3 should be changed to `LLVM_LIBC_SRC___SUPPORT_BIG_INT_H`.