https://svn.boost.org/trac10/ticket/13230 unified headers causing trouble with that..
diff -ur boost.org/libs/filesystem/src/operations.cpp boost/libs/filesystem/src/operations.cpp
--- boost.org/libs/filesystem/src/operations.cpp	2017-11-22 02:21:33.724304181 +0100
+++ boost/libs/filesystem/src/operations.cpp	2017-11-22 02:21:59.686302450 +0100
@@ -11,23 +11,6 @@
 //--------------------------------------------------------------------------------------// 
 
 //  define 64-bit offset macros BEFORE including boost/config.hpp (see ticket #5355) 
-#if !(defined(__HP_aCC) && defined(_ILP32) && !defined(_STATVFS_ACPP_PROBLEMS_FIXED))
-#define _FILE_OFFSET_BITS 64 // at worst, these defines may have no effect,
-#endif
-#if !defined(__PGI)
-#define __USE_FILE_OFFSET64 // but that is harmless on Windows and on POSIX
-      // 64-bit systems or on 32-bit systems which don't have files larger 
-      // than can be represented by a traditional POSIX/UNIX off_t type. 
-      // OTOH, defining them should kick in 64-bit off_t's (and thus 
-      // st_size)on 32-bit systems that provide the Large File
-      // Support (LFS)interface, such as Linux, Solaris, and IRIX.
-      // The defines are given before any headers are included to
-      // ensure that they are available to all included headers.
-      // That is required at least on Solaris, and possibly on other
-      // systems as well.
-#else
-#define _FILE_OFFSET_BITS 64
-#endif
 
 // define BOOST_FILESYSTEM_SOURCE so that <boost/filesystem/config.hpp> knows
 // the library is being built (possibly exporting rather than importing code)