Q. I’m using lighttpd under CentOS 5 and getting the following error:
…can’t handle ‘$HTTP[url] =~ …’ as you compiled without pcre support.

My question is What is pcre support, and how do I solve this problem?

A. Pcre is nothing but Perl-compatible regular expression library. PCRE has its own native API, but a set of “wrapper” functions that are based on
the POSIX API are also supplied in the library libpcreposix. You must compile lighttpd with pcre to support lighttpd regex style config option. pcre-devel package provides the development files (Headers, libraries for static linking, etc) for pcre. Install the following package and rebuild your lighttpd:
# yum install glib2-devel openssl-devel pcre-devel bzip2-devel gzip-devel

Now change directory to lighttpd source code and recompile Lighttpd with pcre option:
# make clean
# ./configure
# make
# make install

Now restart lighttpd and it should support pcre style config options.