uhttpd: update to latest Git HEAD

uhttpd: update to latest Git HEAD

e3395cd ucode: initialize search path before VM init
8cb3f85 ucode: initialize default library search path
188dea2 utils: accept '?' as path terminator in uh_path_match()
c5eac5d file: support using dynamic script handlers as error pages
290ff88 relay: trigger close if in header read state with pending data
f9db538 ucode: ignore exit exceptions
8ba0b64 cmake: use variables and find_library for dependency

Signed-off-by: Jo-Philipp Wich <jo@mein.io>
(backported from commit 4ee77cfcfadcd2b28678a1f3e8e78383b0b21963)