re PR fortran/46020 (Improve error string for BIND(C) diagnostic for len>1 character...

re PR fortran/46020 (Improve error string for BIND(C) diagnostic for len>1 character return type)

PR other/46020
* configure.ac (CXX_FOR_TARGET): Add -funconfigured-libstdc++-v3.
* Makefile.def (CXX_FOR_TARGET): Removed from flags_to_pass.
* Makefile.tpl (CXX_FOR_TARGET_FLAG_TO_PASS): New.
(BASE_FLAGS_TO_PASS): Use it.
* configure: Rebuilt.
* Makefile.in: Rebuilt.

From-SVN: r167160