* Makefile.am (CSHADOW_INCLUDES): Simplify.
* Makefile.in: Regenerate.
* acinclude.m4 (GLIBCPP_ENABLE_SHADOW): Add c_include_dir.
* aclocal.m4: Regenerate.
* mkcheck.in (SRC_DIR): Use it.
* include/bits/std_stdexcept.h: And here.
* include/bits/std_ios.h: Change std_exception.h to exception.
* src/locale.cc: And here.
* src/locale-inst.cc: And here.
* include/bits/valarray_array.h: And here.
* include/bits/stl_alloc.h: And here.
* include/bits/stl_algobase.h: And here.
* include/bits/pthread_allocimpl.h: And here.
* include/bits/stl_construct.h: Change to std_new.h to new.
* include/bits/locale_facets.h: Change std_typeinfo.h to typeinfo.
* libsupc++/include/new: Change stddef.h to cstddef.
* libsupc++/tinfo.h: Change limits.h to climits.
* libsupc++/pure.cc: Comment out _GNU_LIBRARY_ bits, as this
renders the file uncompilable. Add copyright.
* include/c_std/bits/std_cstddef.h: Don't bring wchar_t into std
namespace, as it is a fundamental type.