isc dhcp does not make

[Randy Bush]

FreeBSD dfw0.psg.com 9.0-STABLE FreeBSD 9.0-STABLE #0: Wed Jan 25 21:56:55 UTC 2012     root at dfw0.psg.com:/usr/obj/usr/src/sys/DFW0  amd64

# portupgrade -N net/isc-dhcp42-server
[Gathering depends for net/isc-dhcp42-server ..... done]
--->  Installing 'isc-dhcp42-server-4.2.3_2' from a port (net/isc-dhcp42-server)
--->  Building '/usr/ports/net/isc-dhcp42-server'
===>  Cleaning for isc-dhcp42-server-4.2.3_2
===>  Vulnerability check disabled, database not found
===>  License ISCL accepted by the user
===>  Found saved configuration for isc-dhcp42-server-4.2.3_2
===>  Extracting for isc-dhcp42-server-4.2.3_2
=> SHA256 Checksum OK for dhcp-4.2.3-P2.tar.gz.
===>  Patching for isc-dhcp42-server-4.2.3_2
===>  Applying extra patch /usr/ports/net/isc-dhcp42-server/files/extra-patch-bind__Makefile
===>  Applying FreeBSD patches for isc-dhcp42-server-4.2.3_2
===>   isc-dhcp42-server-4.2.3_2 depends on executable: gmake - found
===>  Configuring for isc-dhcp42-server-4.2.3_2
checking for a BSD-compatible install... /usr/bin/install -c -o root -g wheel
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... ./install-sh -c -d
checking for gawk... gawk
checking whether gmake sets $(MAKE)... yes
checking whether to enable maintainer-specific portions of Makefiles... no
checking for gcc... cc
checking for C compiler default output file name... 
configure: error: C compiler cannot create executables
See `config.log' for more details.
===>  Script "configure" failed unexpectedly.
Please report the problem to zi at FreeBSD.org [maintainer] and attach the
"/usr/ports/net/isc-dhcp42-server/work/dhcp-4.2.3-P2/config.log" including
the output of the failure of your make command. Also, it might be a good idea
to provide an overview of all packages installed on your system (e.g. an `ls
/var/db/pkg`).
*** Error code 1

clang?