Fix the build with gcc when `-Wredundant-decls` is passed

Summary:
gcc warns that `__throw_runtime_error` is declared both in `<__locale>`
and `<stdexcept>`, if `-Wredundant-decls` is passed on the command
line; this is the case with FreeBSD when ${WARNS} == 6.

Since `<__locale>` gets its first declaration via a transitive include
of `<stdexcept>`, and the second declaration is after the first
invocation of `__throw_runtime_error`, delete that second declaration.

Signed-off-by: Enji Cooper <yaneurabeya@gmail.com>

Reviewers: kristina, MaskRay, EricWF, ldionne, ngie

Reviewed By: EricWF

Subscribers: krytarowski, brooks, emaste, dim, christof, jdoerfert, libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D58425


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@354515 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/__locale b/include/__locale
index d1d66f9..0a275c0 100644
--- a/include/__locale
+++ b/include/__locale
@@ -1229,8 +1229,6 @@
 _LIBCPP_EXTERN_TEMPLATE2(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS codecvt_byname<char16_t, char, mbstate_t>)
 _LIBCPP_EXTERN_TEMPLATE2(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS codecvt_byname<char32_t, char, mbstate_t>)
 
-_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void __throw_runtime_error(const char*);
-
 template <size_t _Np>
 struct __narrow_to_utf8
 {