[Bug bootstrap/46810] New: [4.6 regression] sparc64-linux bootstrap fails with "C++ preprocessor "/lib/cpp" fails sanity check"

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46810

           Summary: [4.6 regression] sparc64-linux bootstrap fails with
                    "C++ preprocessor "/lib/cpp" fails sanity check"
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: bootstrap
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mikpe@it.uu.se


Attempting to bootstrap 4.6-20101204 with C++ enabled on sparc64-linux fails
with:

checking how to run the C++ preprocessor... /lib/cpp
configure: error: in `/mnt/scratch/objdir46/gcc':
configure: error: C++ preprocessor "/lib/cpp" fails sanity check
See `config.log' for more details.
make[2]: *** [configure-stage1-gcc] Error 1
make[2]: Leaving directory `/mnt/scratch/objdir46'
make[1]: *** [stage1-bubble] Error 2
make[1]: Leaving directory `/mnt/scratch/objdir46'
make: *** [bootstrap] Error 2

gcc/config.log shows:

...
configure:8444: checking how to run the C++ preprocessor
configure:8471: g++ -E  conftest.cpp
/mnt/scratch/gcc-4.6-20101204/gcc/configure: line 2478: g++: command not found
...
configure:8471: g++ -E  conftest.cpp
/mnt/scratch/gcc-4.6-20101204/gcc/configure: line 2478: g++: command not found
...
configure:8471: /lib/cpp  conftest.cpp
cpp: error trying to exec 'cc1plus': execvp: No such file or directory
...

For the record, my bootstrap compiler only supports C and Ada, not C++.  (C++
should not require C++ for bootstrap, right?)

The previous weekly snapshot gcc-4.6-20101127 did not have this problem.

Configuration:
/mnt/scratch/gcc-4.6-20101204/configure --prefix=/mnt/scratch/install
--with-gmp=/home/mikpe/pkgs/linux-sparc64/gmp-4.3.2
--with-mpfr=/home/mikpe/pkgs/linux-sparc64/mpfr-2.4.2
--with-mpc=/home/mikpe/pkgs/linux-sparc64/mpc-0.8.2 --with-cpu=v8
--enable-multilib --disable-plugin --disable-lto --disable-nls
--enable-threads=posix --enable-checking=release --disable-libmudflap
--enable-languages=c,c++,objc,obj-c++,java,fortran