allocate last zero byte in ngx_crypt()

do not free() stack allocated buffer

use lstat() for WebDAV DELETE, COPY, and MOVE to handle symlinks

opening files fixes:

*) use non-blocking open() not to hang on FIFO files, etc.
*) do not log misleading errno in "not a regular file" error

signal processing stability:

*) use sys_errlist[] in signal handler instead
   of non Async-Signal-Safe strerror_r()
*) do not update time in the timer signal handler,
   since localtime_r() is not Async-Signal-Safe function
*) use previously cached GMT offset value to update time from a signal handler
*) change ngx_time_update() interface since there are no notification methods
   those return time
*) introduce ngx_time_sigsafe_update() to update the error log time only
*) change ngx_time_update() interface

Win32 fixes:

*) compare long file names in case-insensitive mode,
   the bug had been introduced in r3436
*) test default NTFS stream "::$DATA"

Fix a bug introduced in r2032: After a child process has read a terminate
message from a channel, the process tries to read the channel again.
The kernel (at least FreeBSD) may preempt the process and sends a SIGIO
signal to a master process. The master process sends a new terminate message,
the kernel switches again to the the child process, and the child process
reads the messages instead of an EAGAIN error. And this may repeat over
and over. Being that the child process can not exit the cycle and test
the termination flag set by the message handler.

The fix disallow the master process to send a new terminate message on
SIGIO signal reception. It may send the message only on SIGALARM signal.

cache related fixes:

*) do not pass buf with empty cached response,
   this fixes "zero size buf in output" alert
*) hide cacheable Set-Cookie and P3P FastCGI response headers
*) test comma separator in "Cache-Control"
*) a cache manager thread handle was overwritten by a cache loader thread
   handle, this caused an exit delay, the bug had been introduced in r3248
*) fix handling cached HTTP/0.9 response
*) log proxied HTTP/0.9 responses status as "009"
*) fix the "If-None-Match" header name
*) fix a cached zero-length body case

use setproctitle("%s", title)

fix "if (!-x ...)"