Auto-sync with upstream master
    
    Upstream commit: 30200427a99e5ddac9bad08599418d44d54aa9aa
    
    - Add per-thread cache to malloc
    - Add Samoan language locale for Samoa
    - Add Awajún / Aguaruna locale for Peru
    - CVE-2010-3192: Avoid backtrace from __stack_chk_fail (swbz#12189)
    - Add preadv2, writev2 RWF_NOWAIT flag (swbz#21738)
    - Fix abday strings for ar_JO/ar_LB/ar_SY locales (swbz#21749)
    - Fix abday strings for ar_SA locale (swbz#21748, swbz#19066)
    - Set data_fmt for da_DK locale (swbz#17297)
    - Add yesstr and nostr for the zh_HK locale (swbz#21733)
    - Fix abday strings for the ksIN@devanagari locale (swbz#21743)
    - Do not include _dl_resolv_conflicts in libc.a (swbz#21742)
    - Test __memmove_chk, __memset_chk only in libc.so (swbz#21741)
    - Add iI and eE to  yesexpr and noexpr respectively for ts_ZA locale
    - Add yesstr/nostr for kw_GB locale (swbz#21734)
    - Add yesstr and nostr for the ts_ZA locale (swbz#21727)
    - Fix LC_NAME for hi_IN locale (swbz#21729)
    - Add yesstr and nostr for the xh_ZA locale (swbz#21724)
    - Add yesstr and nostr for the zh_CN locale (swbz#21723)
    - Fix full weekday names for the ks_IN@devanagari locale (swbz#21721)
    - Various fixes to Arabic locales after CLDR import