add symbols.h

include/symbols.h

@@ -0,0 +1,45 @@
+/* Heavily stripped down version of glibc include/libc-symbols.h */
+
+/* Support macros for making weak and strong aliases for symbols,
+   and for using symbol sets and linker warnings with GNU ld.
+   Copyright (C) 1995-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef __INCLUDE_SYMBOLS_H
+#define __INCLUDE_SYMBOLS_H
+
+#ifndef C_SYMBOL_NAME
+# define C_SYMBOL_NAME(name) name
+#endif
+
+#ifndef __ASSEMBLER__
+
+/* Define ALIASNAME as a weak alias for NAME.
+   If weak aliases are not available, this defines a strong alias.  */
+# define weak_alias(name, aliasname) _weak_alias (name, aliasname)
+# define _weak_alias(name, aliasname) \
+  extern __typeof (name) aliasname __attribute__ ((weak, alias (#name)));
+
+#else
+
+# define weak_alias(original, alias)                                    \
+  .weak C_SYMBOL_NAME (alias) ;                                         \
+  C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
+
+#endif
+
+#endif