Auto-sync with upstream branch master
    
    Upstream commit: 1b7f04070bd94f259e2ed24d6fb76309d64fb164.
    
    - locale: Avoid zero-length array in _nl_category_names [BZ #24962]
    - math: Replace const attribute with pure in totalorder* functions
    - y2038: Introduce the __ASSUME_TIME64_SYSCALLS define
    - Finish move of clock_* functions to libc. [BZ #24959]
    - Update Alpha libm-test-ulps
    - localedef: Use initializer for flexible array member [BZ #24950]
    - Add misc/tst-mntent-autofs, testing autofs "ignore" filtering
    - Use autofs "ignore" mount hint in getmntent_r/getmntent
    - hurd: Fix build
    - Use generic memset/memcpy/memmove in benchtests
    - nptl: Move pthread_attr_getinheritsched implementation into libc
    - hurd: Fix SS_ONSTACK support
    - hurd: Remove optimizing anonymous maps as __vm_allocate.
    - hurd: Fix poll and select POSIX compliancy details about errors
    - hurd: Fix timeout handling in _hurd_select
    - hurd getcwd: Allow unknown root directory
    - hurd: Fix implementation of setitimer.
    - hurd: Fix _hurd_select for single fd sets
    - MIPS support for GNU hash
    - sh: Split BE/LE abilist
    - microblaze: Split BE/LE abilist
    - arm: Split BE/LE abilist
    - Correct the spelling of more contributors
    - Fix posix/tst-regex by using UTF-8 and own test input
    - [powerpc] fegetenv_status: simplify instruction generation
    - [powerpc] fesetenv: optimize FPSCR access
    - [powerpc] SET_RESTORE_ROUND improvements
    - [powerpc] fe{en,dis}ableexcept, fesetmode: optimize FPSCR accesses
    - [powerpc] fe{en,dis}ableexcept optimize bit translations
    - misc: Use allocate_once in getmntent
    - nptl: Move pthread_attr_setdetachstate implementation into libc
    - login: pututxline could fail to overwrite existing entries [BZ #24902]
    - Fix posix/tst-regex by using a dedicated input-file.