glibc: update to latest 2.27 commit (BZ#23637)

5b4f7382af Add undef to fix test failure.
9456483fb2 Improve performance of memmem
373f8b06a3 Improve performance of strstr
4ec1b9e913 Fix strstr bug with huge needles (bug 23637)
ecd6271ed8 Speedup first memmem match
bba6b9288f Simplify and speedup strstr/strcasestr first match
7a4da6ef7a Improve strstr performance

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>