/usr/include/mongo/platform/ is in mongodb-dev 1:2.4.9-1ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/mongo/platform/atomic_intrinsics.h
/usr/include/mongo/platform/atomic_intrinsics_gcc_generic.h
/usr/include/mongo/platform/atomic_intrinsics_gcc_intel.h
/usr/include/mongo/platform/atomic_intrinsics_win32.h
/usr/include/mongo/platform/atomic_word.h
/usr/include/mongo/platform/backtrace.h
/usr/include/mongo/platform/basic.h
/usr/include/mongo/platform/bits.h
/usr/include/mongo/platform/compiler.h
/usr/include/mongo/platform/compiler_gcc.h
/usr/include/mongo/platform/compiler_msvc.h
/usr/include/mongo/platform/cstdint.h
/usr/include/mongo/platform/float_utils.h
/usr/include/mongo/platform/posix_fadvise.h
/usr/include/mongo/platform/random.h
/usr/include/mongo/platform/strcasestr.h
/usr/include/mongo/platform/strtoll.h
/usr/include/mongo/platform/unordered_map.h
/usr/include/mongo/platform/unordered_set.h
/usr/include/mongo/platform/windows_basic.h