Auto-sync with upstream master
    
    Upstream commit: 5f9409b787c5758fc277f8d1baf7478b752b775d
    
    - Drop glibc-rh952799.patch, applied upstream (#952799, swbz#22025)
    - Various locale fixes (swbz#22022, swbz#22038, swbz#21951, swbz#13805,
      swbz#21971, swbz#21959)
    - MIPS/o32: Fix internal_syscall5/6/7 (swbz#21956)
    - AArch64: Fix procfs.h not to expose stdint.h types
    - iconv_open: Fix heap corruption on gconv_init failure (swbz#22026)
    - iconv: Mangle __btowc_fct even without __init_fct (swbz#22025)
    - Fix bits/math-finite.h _MSUF_ expansion namespace (swbz#22028)
    - Provide a C++ version of iszero that does not use __MATH_TG (swbz#21930)