uhttpd: update to latest Git head

uhttpd: update to latest Git head

cdfc902 cgi: escape url in 403 error output
0bba1ce uhttpd: fix building without TLS and Lua support
2ed3341 help: document -A option
fa5fd45 file: fix CPP syntax error
77b774b build: avoid redefining _DEFAULT_SOURCE
b741dec lua: support multiple Lua prefixes
952bf9d build: use _DEFAULT_SOURCE
30a18cb uhttpd: recognize PATCH, PUT and DELETE HTTP methods
796d42b client: flush buffered SSL output when tearing down client ustream
393b59e proc: expose HTTP Origin header in process environment
8109b95 file: escape strings in HTML output
d3b9560 utils: add uh_htmlescape() helper
db86175 lua: honour size argument in recv()

Signed-off-by: Jo-Philipp Wich <jo@mein.io>