I cannot build pkgsrc-2006Q2 devel/libltdl on linux with the following error
Adding USE_LANGUAGES=c c++ solves this problem.
Can anybody commit this addition to HEAD and/or branch?

0 libltdl>/usr/pkg/bin/bmake      
===> Skipping vulnerability checks.
WARNING: No /home/cheusov/pkgsrc/distfiles/pkg-vulnerabilities file found.
WARNING: To fix, install the pkgsrc/security/audit-packages
WARNING: package and run: ``/usr/pkg/sbin/download-vulnerability-list''.
=> Checksum SHA1 OK for libtool-1.5.22.tar.gz.
=> Checksum RMD160 OK for libtool-1.5.22.tar.gz.
work.cheusov -> /home/cheusov/tmp/pkgsrc/devel/libltdl/work.cheusov
===> Installing dependencies for libltdl-1.5.22
=> Required installed package libtool-base>=1.5.18nb5: libtool-base-1.5.22nb3 found
===> Overriding tools for libltdl-1.5.22
===> Extracting for libltdl-1.5.22
===> Patching for libltdl-1.5.22
=> Applying pkgsrc patches for libltdl-1.5.22
===> Creating toolchain wrappers for libltdl-1.5.22
===> Configuring for libltdl-1.5.22
configure: WARNING: If you wanted to set the --build type, don't use --host.
    If a cross compiler is detected then cross compile mode will be used.
checking for a BSD-compatible install... /usr/bin/install -c -o root -g root
checking whether build environment is sane... yes
checking for gawk... /usr/bin/awk
checking whether make sets $(MAKE)... yes
checking for i386-debian-linux-strip... no
checking for strip... strip
configure: WARNING: In the future, Autoconf will not detect cross-tools
whose name does not start with the host triplet.  If you think this
configuration is useful to you, please write to autoconf@gnu.org.
checking for i386-debian-linux-gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables... 
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking for style of include used by make... GNU
checking dependency style of gcc... none
checking for a sed that does not truncate output... (cached) /bin/sed
checking build system type... i686-pc-linux-gnu
checking host system type... i386-debian-linux-gnu
checking for grep that handles long lines and -e... (cached) /bin/grep
checking for egrep... (cached) /bin/egrep
checking for ld used by gcc... (cached) ld
checking if the linker (ld) is GNU ld... yes
checking for BSD-compatible nm... nm
checking whether ln -s works... yes
checking whether we are using the GNU C++ compiler... no
checking whether g++ accepts -g... no
checking dependency style of g++... none
checking for i386-debian-linux-g77... f77
checking whether we are using the GNU Fortran 77 compiler... no
checking whether f77 accepts -g... no
checking for i386-debian-linux-gcj... no
checking for gcj... no
checking for i386-debian-linux-windres... no
checking for windres... no
checking for ld option to reload object files... -r
checking how to recognise dependent libraries... pass_all
checking how to run the C preprocessor... gcc -E
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking dlfcn.h usability... yes
checking dlfcn.h presence... yes
checking for dlfcn.h... yes
checking how to run the C++ preprocessor... cpp
configure: error: C++ preprocessor "cpp" fails sanity check
See `config.log' for more details.
*** Error code 1

Stop.
bmake: stopped in /home/cheusov/pkgsrc/devel/libltdl
===> 
===> There was an error during the ``configure'' phase.
===> Please investigate the following for more information:
===>      * config.log
===>      * /home/cheusov/tmp/pkgsrc/devel/libltdl/work.cheusov/.work.log
===> 
*** Error code 1

Stop.
bmake: stopped in /home/cheusov/pkgsrc/devel/libltdl
1 libltdl>

-- 
Best regards, Aleksey Cheusov.