Update from 0.7.45 to 0.7.47.

<ChangeLog>

*) Bugfix: nginx could not be built on FreeBSD 6 and early versions;

the bug had appeared in 0.7.46.

*) Bugfix: nginx could not be built on MacOSX; the bug had

appeared in 0.7.46.

*) Bugfix: if the "max_size" parameter was set, then the cache manager

might purge a whole cache; the bug had appeared in 0.7.46.

*) Change: a segmentation fault might occur in worker process, if the

"proxy_cache"/"fastcgi_cache" and the "proxy_cache_valid"/
"fastcgi_cache_valid" were set on different levels; the bug had
appeared in 0.7.46.

*) Bugfix: a segmentation fault might occur in worker process, if a

request was redirected to a proxied or FastCGI server via error_page
or try_files; the bug had appeared in 0.7.44.

</ChangeLog>