maintain physical.basedir (the "acting" doc-root as prefix of physical.path) in more places

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2926 152afb58-edef-0310-8abb-c4023f1b3aa9
[core] decode URL before rewrite, enabling it to work in $HTTP["url"] conditionals (fixes #2526)

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2927 152afb58-edef-0310-8abb-c4023f1b3aa9
[auto* build] remove -no-undefined from linker flags, as we actually link modules with undefined symbols (fixes #2533)

On platforms that support linking modules with undefined symbols we
actually do it; so most of the time -no-undefined should result in an
error.
On platforms that don't support it, it will result in an error sooner or
later anyway (on those it should build a shared libary with the core
code to link the modules against).

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2928 152afb58-edef-0310-8abb-c4023f1b3aa9