Auto-sync with upstream branch master
    
    Upstream commit: 466c1ea15f461edb8e3ffaf5d86d708876343bbf
    
    - dlfcn: Rework static dlopen hooks
    - dlfcn: Eliminate GLIBC_PRIVATE dependency from tststatic2
    - dlfcn: Cleanups after -ldl is no longer required
    - dlfcn: Move dlopen into libc
    - dlfcn: Move dlvsym into libc
    - dlfcn: Move dlinfo into libc
    - dlfcn: Move dladdr1 into libc
    - dlfcn: Move dlmopen into libc
    - dlfcn: Move dlsym into libc
    - dlfcn: Move dladdr into libc
    - dlfcn: Move dlclose into libc
    - Improve test coverage of strlen function
    - fix typo
    - dlfcn: Move dlerror into libc
    - Add libc ABI extension kludge for baseline-violating libdl symbols
    - scripts/versions.awk: Add local: * to all version nodes
    - Add missing symbols to Version files
    - Fix use of __pthread_attr_copy in mq_notify (bug 27896)
    - Use __pthread_attr_copy in mq_notify (bug 27896)
    - Update floating-point feature test macro handling for C2X
    - stdio-common: Remove _IO_vfwscanf
    - aarch64: align stack in clone [BZ #27939]
    - powerpc: Optimized memcmp for power10
    - x86-64: Align child stack to 16 bytes [BZ #27902]