Compile/Configure error on RH-Linux 9.0..

[Rex Mueller]

checking netinet/in_systm.h presence... yes
checking for netinet/in_systm.h... yes
checking netinet/ip.h usability... yes
checking netinet/ip.h presence... yes
checking for netinet/ip.h... yes
checking netinet/ip_icmp.h usability... yes
checking netinet/ip_icmp.h presence... yes
checking for netinet/ip_icmp.h... yes
checking netinet/tcp.h usability... yes
checking netinet/tcp.h presence... yes
checking for netinet/tcp.h... yes
checking netinet/udp.h usability... yes
checking netinet/udp.h presence... yes
checking for netinet/udp.h... yes
checking ethertype.h usability... no
checking ethertype.h presence... no
checking for ethertype.h... no
checking pcap.h usability... yes
checking pcap.h presence... yes
checking for pcap.h... yes
checking linux/if_pppox.h usability... no
checking linux/if_pppox.h presence... yes
configure: WARNING: linux/if_pppox.h: present but cannot be compiled
configure: WARNING: linux/if_pppox.h: check for missing prerequisite headers?
configure: WARNING: linux/if_pppox.h: proceeding with the preprocessor's result
configure: WARNING:     ## ------------------------------------ ##
configure: WARNING:     ## Report this to address@hidden. ##
configure: WARNING:     ## ------------------------------------ ##
checking for linux/if_pppox.h... yes
checking crypt.h usability... yes
checking crypt.h presence... yes
checking for crypt.h... yes
checking pwd.h usability... yes
checking pwd.h presence... yes
checking for pwd.h... yes
checking security/pam_appl.h usability... yes
checking security/pam_appl.h presence... yes
checking for security/pam_appl.h... yes
checking shadow.h usability... yes
checking shadow.h presence... yes
checking for shadow.h... yes
checking locale.h usability... yes
checking locale.h presence... yes
checking for locale.h... yes
checking langinfo.h usability... yes
checking langinfo.h presence... yes
checking for langinfo.h... yes
checking dirent.h usability... yes
checking dirent.h presence... yes