Error after including boost/thread/detail/platform_time.hpp

The header `#include ` has been added in Boost 1.69.0.
It includes another header `#include ` which causes conflict on MAC OS when used with `#include `. Conflicts are for various identifier which are already defined in MachO.h.

Error :
In the error below `vm_prot.h `gets included by `mach_time.h` (seen by generating preprocessor output)

```
llvm/Support/MachO.h:527:7: error: expected identifier
VM_PROT_READ = 0x1,
^
/Applications/Xcode10.1.0.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/usr/include/mach/vm_prot.h:83:22: note: expanded from macro 'VM_PROT_READ'
#define VM_PROT_READ ((vm_prot_t) 0x01) /* read permission */
```

Sample program when compiled on MAC, generates the same error:

```
#include
#include

int main()
{
return 0;
}
```