re PR c/81854 (weak alias of an incompatible symbol accepted)

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

From-SVN: r253153

libstdc++-v3/ChangeLog

+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.
+
 2017-09-21  Jonathan Wakely  <jwakely@redhat.com>
 
 	* testsuite/25_algorithms/clamp/1.cc: Fix order of arguments and

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);