What is the path to 'apxs'? On my Gentoo it is /usr/sbin/apxs2
$ ./autogen.sh ... checking what the shared library extension is... could not determine shared library extension. Defaulting to .so .so checking for apxs... configure: error: could not generate includes with apxs set to "" - you must specify a valid path to apxs using the --with-apxs flag Now type 'make' to compile mod_cplusplus. $ ./configure --with-apxs=/usr/sbin/apxs2