Auto-sync with upstream branch master
    
    Upstream commit: b1caa144c74678097cada5a54eda2996bb459d8f
    
    - Update mips libm-test-ulps
    - Update alpha libm-test-ulps
    - Update ia64 libm-test-ulps
    - Update sparc libm-test-ulps
    - Update arm libm-test-ulps
    - Update aarch64 libm-test-ulps
    - Updates to the shn_MM locale [BZ #25532]
    - powerpc: Update ULPs and xfail more ibm128 outputs
    - i386: Remove build support for GCC older than GCC 6
    - oc_FR locale: Fix spelling of April (bug 25639)
    - Update hppa libm-test-ulps
    - y2038: linux: Provide __mq_timedreceive_time64 implementation
    - y2038: linux: Provide __mq_timedsend_time64 implementation
    - y2038: include: Move struct __timespec64 definition to a separate file
    - malloc: ensure set_max_fast never stores zero [BZ #25733]
    - powerpc64le: enforce non-specific long double in .gnu.attributes section
    - powerpc64le: workaround ieee long double / _Float128 stdc++ bug
    - powerpc64le: Enforce -mabi=ibmlongdouble when -mfloat128 used
    - powerpc64le/multiarch: don't generate strong aliases for fmaf128-ppc64
    - ldbl-128ibm: simplify iscanonical.h
    - i386: Disable check_consistency for GCC 5 and above [BZ #25788]
    - Add IPPROTO_ETHERNET and IPPROTO_MPTCP from Linux 5.6 to netinet/in.h.
    - Update syscall lists for Linux 5.6.
    - elf: Implement DT_AUDIT, DT_DEPAUDIT support [BZ #24943]
    - elf: Simplify handling of lists of audit strings
    - support: Change xgetline to return 0 on EOF
    - nptl: Remove x86_64 cancellation assembly implementations [BZ #25765]
    - aarch64: update bits/hwcap.h
    - Add tests for Safe-Linking
    - S390: Regenerate ULPs.
    - sysv/alpha: Use generic __timeval32 and helpers
    - linux: Use long time_t for wait4/getrusage
    - resource: Add a __rusage64 struct
    - linux: Use long time_t __getitimer/__setitimer
    - sysv: Define __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64
    - math: Add inputs that yield larger errors for float type (x86_64)