Fix most GCC warnings during build. Only -Wattribute left.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@246280 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/system_error b/include/system_error
index 66bf6d6..134bb32 100644
--- a/include/system_error
+++ b/include/system_error
@@ -371,7 +371,7 @@
     error_category() _NOEXCEPT;
 #else
     _LIBCPP_ALWAYS_INLINE
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 error_category() _NOEXCEPT _LIBCPP_DEFAULT;
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 error_category() _NOEXCEPT _LIBCPP_DEFAULT
 #endif
 private:
     error_category(const error_category&);// = delete;