Auto-sync with upstream branch master
    
    Upstream commit: 0ddb7ea842abf63516b74d4b057c052afc6ba863.
    
    - nptl: Assume __ASSUME_FUTEX_CLOCK_REALTIME support
    - powerpc: Fix build of wcscpy with --disable-multi-arch
    - elf: Remove remnants of MAP_ANON emulation
    - S390: Increase function alignment to 16 bytes.
    - ja_JP: Change the offset for Taisho gan-nen from 2 to 1 [BZ #24162]
    - ldbl-opt: Reuse test cases from misc/ that check long double
    - ldbl-opt: Add error and error_at_line (bug 23984)
    - ldbl-opt: Add err, errx, verr, verrx, warn, warnx, vwarn, and vwarnx (bug 23984)
    - ldbl-opt: Reuse argp tests that print long double
    - ldbl-opt: Add argp_error and argp_failure (bug 23983)
    - elf/tst-big-note: Improve accuracy of test [BZ #20419]
    - S390: Fix introduction of __wcscpy and weak wcscpy symbols.
    - __netlink_assert_response: Add more __libc_fatal newlines [BZ #20271]
    - Add more spaces before '('.
    - elf: Add tests with a local IFUNC resolver [BZ #23937]
    - elf/Makefile: Run IFUNC tests if binutils supports IFUNC
    - powerpc: Fix linknamespace introduced by 4d8015639a75
    - hurd: Add renameat2 support for RENAME_NOREPLACE
    - Fix -Wempty-body warnings in Hurd-specific code.
    - Add some spaces before '('.
    - wcsmbs: optimize wcsnlen
    - wcsmbs: optimize wcsncpy
    - wcsmbs: optimize wcsncat
    - wcsmbs: optimize wcscpy
    - wcsmbs: optimize wcscat
    - wcsmbs: optimize wcpncpy
    - wcsmbs: optimize wcpcpy
    - Break further lines before not after operators.
    - Add and move fall-through comments in system-specific code.