uhttpd: update to Git HEAD (2026-05-15)

uhttpd: update to Git HEAD (2026-05-15)

d2551871b5e5 client: prevent transfer_chunked counter overflow
07f0afb3bf91 client: match Host and URL attributes exactly in tls_redirect_check
05406f70d05c file: scan all entries when matching If-Match / If-None-Match
81527e1f7630 proc: restore default SIGPIPE disposition in spawned child
0df62571f158 ucode: initialize module search path only once
05317bf30a94 proc: store CGI Status message per-client instead of in a shared buffer
1781b6dec414 utils, client: cast char to unsigned before passing to ctype functions
4221eb8b33ea file: respond 500 on uh_handle_alias OOM
8e5b26f93798 file: distinguish parse failure from epoch in date precondition checks
ced7b15c3467 utils: fix one-byte overflow in uh_urldecode
53e7150619a3 file: bail out of file_write_cb on read error
93432149a7ae utils: remove unreachable return statement in uh_addr_rfc1918
add5389470f0 utils: fix off-by-one out-of-bounds read in uh_b64decode
778ccbbf5f8a main: fix daemonization stdio redirection and fd leak
2c869c094c25 client: parse Content-Length safely
9404e6c62bb7 client: parse chunked transfer chunk size safely
b33ca5d37718 auth: do not accept stored crypt hash as plaintext password
6fadf0da5050 auth: replace strcmp with constant-time password comparison

Link: https://github.com/openwrt/openwrt/pull/23379
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>