When compiling mod_ruby under Fedora Core 5, and thus Apache 2.2, configure.rb assumes an incorrect path for the apr* files, and make kicked out the following errors:

# make
In file included from /usr/include/httpd/httpd.h:43,
from mod_ruby.h:49,
from mod_ruby.c:33:
/usr/include/httpd/ap_config.h:25:17: error: apr.h: No such file or directory
/usr/include/httpd/ap_config.h:26:23: error: apr_hooks.h: No such file or directory
/usr/include/httpd/ap_config.h:27:32: error: apr_optional_hooks.h: No such file or directory
…

The problem is that the apr* files are in /usr/include/apr-1, which is not where make is looking. (In order to compile mod_ruby, the httpd-devel, apr-devel, and apr-util-devel packages are required, so doing a “yum install httpd-devel” installs these three packages).

To fix the problem, run the configure.rb command like this:

./configure.rb –with-apr-includes=/usr/include/apr-1

and then the “make” command will run without error.