Resolves: #1462820
    
    - Drop glibc-Disable-buf-NULL-in-login-tst-ptsname.c, applied upstream.
    - Auto-sync with upstream master,
      commit 37e9dc814636915afb88d0779e5e897e90e7b8c0, fixing:
    - CVE-2017-1000366: Avoid large allocas in the dynamic linker (#1462820)
    - wait3 namespace (swbz#21625)
    - S390: Sync ptrace.h with kernel (swbz#21539)
    - Another x86 sys/ucontext.h namespace issue (swbz#21457)
    - siginterrupt namespace (swbz#21597)
    - Signal stack namespace (swbz#21584)
    - Define struct rusage in sys/wait.h when required (swbz#21575)
    - S390: Fix build with gcc configured with --enable-default-pie (swbz#21537)
    - Update timezone code from tzcode 2017b
    - nptl: Invert the mmap/mprotect logic on allocated stacks (swbz#18988)
    - PowerPC64 ELFv2 PPC64_OPT_LOCALENTRY
    - Make copy of <bits/std_abs.h> from GCC (swbz#21573)
    - localedata: ce_RU: update weekdays from CLDR (swbz#21207)
    - localedata: Remove trailing spaces (swbz#20275)
    - XPG4 bsd_signal namespace (swbz#21552)
    - Correct collation rules for Malayalam (swbz#19922, swbz#19919)
    - waitid namespace (swbz#21561)
    - Condition signal.h inclusion in sys/wait.h (swbz#21560)
    - ld.so: Consolidate 2 strtouls into _dl_strtoul (swbz#21528)
    - tst-timezone race (swbz#14096)
    - Define SIG_HOLD for XPG4 (swbz#21538)
    - struct sigaltstack namespace (swbz#21517)
    - sigevent namespace (swbz#21543)
    - Add shim header for bits/syscall.h (swbz#21514)
    - namespace issues in sys/ucontext.h (swbz#21457)
    - posix: Implement preadv2 and pwritev2
    - Various float128 and tunables improvements