Auto-sync with upstream branch master
    
    Upstream commit: 797ba44ba27521261f94cc521f1c2ca74f650147
    
    - CVE-2017-15670: glob: Fix one-byte overflow (#1504807)
    - math: Add bits/floatn.h defines for more _FloatN / _FloatNx types
    - posix: Fix improper assert in Linux posix_spawn (swbz#22273)
    - x86-64: Use fxsave/xsave/xsavec in _dl_runtime_resolve (swbz#21265)
    - malloc: Add single-threaded path to _int_free
    - locale: Add new locale kab_DZ (swbz#18812)
    - locale: Add new locale shn_MM (swbz#13605)