fenv.h on Ubuntu

fenv.h on Ubuntu

plus fix the ordering of the patches:

* inclhack.def: many of the headers found under "bits/" are
  often stashed under architecture directories.  Apply fixes
  to those, too.  Also, re-ordered misordered fixes.
* tests/base/linux/vt.h: 80 columns in .def file limitation
* tests/base/iso/math_c99.h: adjust ordering
* tests/base/rtldef/string.h: likewise
* tests/base/bits/fenv.h: likewise
* tests/base/pthread.h: likewise

From-SVN: r205793