Error: Target org.macports.configure returned: configure failure

[Skiff X]

When I try to install anything whether its nmap or wget, I get the  
same error:
$ sudo port install nmap
Password:
--->  Configuring libpcap
Error: Target org.macports.configure returned: configure failure:  
shell command " cd "/opt/local/var/macports/build/ 
_opt_local_var_macports_sources_rsync 
.macports.org_release_ports_net_libpcap/work/libpcap-1.0.0" && ./ 
configure --prefix=/opt/local --enable-ipv6 " returned error 77
Command output: checking build system type... i686-apple-darwin9.6.0
checking host system type... i686-apple-darwin9.6.0
checking target system type... i686-apple-darwin9.6.0
checking for gcc... /usr/bin/gcc-4.0
checking for C compiler default output file name...
configure: error: C compiler cannot create executables
See `config.log' for more details.

Error: The following dependencies failed to build: libpcap openssl  
zlib pcre readline ncurses ncursesw
Error: Status 1 encountered during processing.


Anyone knows how to resolve this issue?

Thanks in advance.