Stuck installing ruby-fcgi on Linux


I've installed fcgi 2.4.0 on a CentOS 4.2 box without problems using:

[root@machine fcgi-2.4.0]# ./configure --prefix=/usr --exec-prefix=/usr
&& make && make install

When I try to install ruby-fcgi bindings I get the following:

[root@machine ruby-fcgi-0.8.6]# ruby install.rb config --
--with-fcgi-lib=/usr/lib/ --with-fcgi-include=/usr/include/
install.rb: entering config phase...
---> lib
<--- lib
---> ext
---> ext/fcgi
/usr/bin/ruby /root/install/ruby-fcgi-0.8.6/ext/fcgi/extconf.rb
--with-fcgi-lib=/usr/lib/ --with-fcgi-include=/usr/include/
checking for fcgiapp.h... yes
checking for FCGX_Accept() in -lfcgi... no
<--- ext/fcgi
<--- ext
install.rb: config done.

For some reason, the ruby-fcgi picks up the header file alright, but
not the lib dir. Any hints on why are greatly appreciated as I'm quite
stuck here.