[PATCH, libstdc++]: Fix another instance of -Werror=attributes bootststrap failure

[Uros Bizjak]

Hello!

Attached patch fixes -Werror=attributes bootstrap failure on
alphaev68-linux-gnu. The patch declares the alias without a prototype,
as suggested in [1].

2017-09-25  Uros Bizjak  <ubizjak@gmail.com>

    PR c/81854
    * src/c++98/complex_io.cc (_GLIBCXX_LDBL_COMPAT): Declare alias
    target as a C++ function with no prototype.

Bootstrapped and regression tested on alphaev68-linux-gnu.

OK for mainline?

[1] https://gcc.gnu.org/ml/libstdc++/2017-08/msg00025.html

Uros.
-------------- next part --------------
diff --git a/libstdc++-v3/src/c++98/complex_io.cc b/libstdc++-v3/src/c++98/complex_io.cc
index bb09ca5..f55e322 100644
--- a/libstdc++-v3/src/c++98/complex_io.cc
+++ b/libstdc++-v3/src/c++98/complex_io.cc
@@ -95,7 +95,7 @@ _GLIBCXX_END_NAMESPACE_VERSION
 #ifdef _GLIBCXX_LONG_DOUBLE_COMPAT
 
 #define _GLIBCXX_LDBL_COMPAT(dbl, ldbl) \
-  extern "C" void ldbl (void) __attribute__ ((alias (#dbl), weak))
+  extern "C" void ldbl (...) __attribute__ ((alias (#dbl), weak))
 
 _GLIBCXX_LDBL_COMPAT (_ZStlsIdcSt11char_traitsIcEERSt13basic_ostreamIT0_T1_ES6_RKSt7complexIT_E,
 		      _ZStlsIecSt11char_traitsIcEERSt13basic_ostreamIT0_T1_ES6_RKSt7complexIT_E);