Autoconf 2.57 & Freebsd 5 release

[Felipe Gustavo de Almeida]

I've got this:

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:     ## ------------------------------------ ##


and this:

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:     ## ------------------------------------ ##


while ./configuring curl 7.10.3 from freebsd ports
using  Autoconf 2.57 and FreeBSD5 RELEASE