the build (compile) process fails due to: ntp_config.c:1619: `CONFIG_PHONE' undeclared (first use in this function) i came to the conclusion, that this error is due to a line in /usr/src/linux/include/asm/param.h: #include <linux/autoconf.h> (which undefines that macro, if the kernel is conf. w/o telephony services.) ... a nice clash of C macros (once used internally by ntp, once undefined by a configuration of the kernel). But the strange thing is, that the #include line in param.h is only for certain kernel configuration. I don't know why.
it was my fault. I symlinked /usr/include/linux -> /usr/src/linux/include/linux and asm -> asm. I don't know why in Gentoo it is not the right thing to do. (i was used to do it for years).
http://cvs.gentoo.org/cgi-bin/viewcvs.cgi/gentoo-x86/net-misc/ntp/files/linux-config-phone.patch?rev=1.1&content-type=text/vnd.viewcvs-markup there you guys go