darwin autoconf bugs

[Jean-Pierre Mouilleseaux]

on darwin ppc 6.3

checking arpa/inet.h usability... yes
checking arpa/inet.h presence... yes
checking for arpa/inet.h... yes
checking net/if.h usability... no
checking net/if.h presence... yes
configure: WARNING: net/if.h: present but cannot be compiled
configure: WARNING: net/if.h: check for missing prerequisite headers?
configure: WARNING: net/if.h: proceeding with the preprocessor's result
configure: WARNING:     ## ------------------------------------ ##
configure: WARNING:     ## Report this to address@hidden ##
configure: WARNING:     ## ------------------------------------ ##
checking for net/if.h... yes
checking netinet/in.h usability... yes
checking netinet/in.h presence... yes
checking for netinet/in.h... yes
checking netinet/if_ether.h usability... no
checking netinet/if_ether.h presence... yes
configure: WARNING: netinet/if_ether.h: present but cannot be compiled
configure: WARNING: netinet/if_ether.h: check for missing prerequisite 
headers?
configure: WARNING: netinet/if_ether.h: proceeding with the 
preprocessor's result
configure: WARNING:     ## ------------------------------------ ##
configure: WARNING:     ## Report this to address@hidden ##
configure: WARNING:     ## ------------------------------------ ##
checking for netinet/if_ether.h... yes
checking netdb.h usability... yes
checking netdb.h presence... yes
checking for netdb.h... yes
checking sys/select.h usability... yes
checking sys/select.h presence... yes
checking for sys/select.h... yes
checking sys/socket.h usability... yes
checking sys/socket.h presence... yes
checking for sys/socket.h... yes
checking sys/sockio.h usability... yes
checking sys/sockio.h presence... yes
checking for sys/sockio.h... yes