Auto-sync with upstream branch master,
    
    Upstream commit: e0cb7b6131ee5f2dca2938069b8b9590304e6f6b
    
    - nss_files: Fix /etc/aliases null pointer dereference (swbz#24059)
    - regex: fix read overrun (swbz#24114)
    - libio: use stdout in puts and putchar, etc (swbz#24051)
    - aarch64: Add AmpereComputing emag to tunable cpu list
    - aarch64: Optimized memset specific to AmpereComputing emag
    - aarch64: Optimized memchr specific to AmpereComputing emag
    - Require GCC 6.2 or later to build glibc
    - manual: Document lack of conformance of sched_* functions (swbz#14829)
    - libio: Use stdin consistently for input functions (swbz#24153)
    - x86-64 memcmp: Use unsigned Jcc instructions on size (swbz#24155)
    - Fix handling of collating elements in fnmatch (swbz#17396,swbz#16976)
    - arm: Use "nr" constraint for Systemtap probes (swbz#24164)
    - Fix alignment of TLS variables for tls variant TLS_TCB_AT_TP (swbz#23403)
    - Add compiler barriers for pthread_mutex_trylock (swbz#24180)
    - rt: Turn forwards from librt to libc into compat symbols (swbz#24194)
    - Linux: Add gettid system call wrapper (swbz#6399)
    - nptl: Avoid fork handler lock for async-signal-safe fork (swbz#24161)
    - elf: Ignore LD_AUDIT interfaces if la_version returns 0 (swbz#24122)
    - nptl: Reinstate pthread_timedjoin_np as a cancellation point (swbz#24215)
    - nptl: Fix invalid Systemtap probe in pthread_join (swbz#24211)