twice termination delay only after SIGALRM, otherwise many separate SIGCHLD
and SIGIO signals quickly increase delay to the level when SIGKILL is sent

process upstream ETag header

the flags should be bit-wide only

fix invalid header logging:

*) fix segfault when a header starts with "\rX"
   and logging is set to info or debug level
*) use %*s instead of %V

FastCGI fixes:

*) continue to parse available fastcgi record after a split header,
   this fixes the erroneous message "upstream prematurely closed connection
   while reading response header from upstream"
*) fix a garbage in a split fastcgi header
*) refactor fastcgi stderr handling

XSLT filter fixes:

*) preserve XML wellFormed field before freeing memory
*) fix libxml2 error message

win32 fixes:

*) ngx_http_set_exten() is always successful since 0.3.46
*) skip URI trailing dots under Win32
*) use caseless regex locations on caseless filesystems: MacOSX, Win32, Cygwin

handle Win32 ReadFile() EOF state in Unix way

*) $upstream_cache_status
*) clean cache updating state if a response has uncacheable code or
   cache prohibitive headers