Auto-sync with upstream branch master
    
    Upstream commit: bfdb731438206b0f70fe7afa890681155c30b419
    
    - rtld: Check __libc_enable_secure for LD_PREFER_MAP_32BIT_EXEC (CVE-2019-19126)
    - Introduce DL_LOOKUP_FOR_RELOCATE flag for _dl_lookup_symbol_x
    - Enable inlining issignalingf within glibc
    - Don't use a custom wrapper macro around __has_include (bug 25189).
    - Remove duplicate inline implementation of issignalingf
    - misc: Set generic pselect as ENOSYS
    - Use DEPRECATED_SCANF macro for remaining C99-compliant scanf functions
    - ldbl-128ibm-compat: Add regular/wide character printing printing functions
    - ldbl-128ibm-compat: Test double values and positional arguments
    - ldbl-128ibm-compat: Add regular/wide character scanning functions
    - arm: Fix armv7 selection after 'Split BE/LE abilist'
    - Use Linux 5.4 in build-many-glibcs.py.
    - sysdeps/posix: Simplify if expression in getaddrinfo
    - sysdeps/posix/getaddrinfo: Return early on invalid address family
    - ru_UA locale: use copy "ru_RU" in LC_TIME (bug 25044)
    - locale: Greek -> ASCII transliteration table [BZ #12031]
    - nptl: Cleanup mutex internal offset tests
    - nptl: Add tests for internal pthread_rwlock_t offsets
    - nptl: Remove rwlock elision definitions
    - nptl: Add struct_mutex.h and struct_rwlock.h
    - nptl: Add default pthreadtypes-arch.h and pthread-offsets.h
    - Compile elf/rtld.c with -fno-tree-loop-distribute-patterns.
    - nptl: Fix __PTHREAD_MUTEX_INITIALIZER for !__PTHREAD_MUTEX_HAVE_PREV
    - S390: Fix handling of needles crossing a page in strstr z15 ifunc [BZ #25226]