[2/5] Add common ifunc-init.h header

diff --git a/sysdeps/generic/ifunc-init.h b/sysdeps/generic/ifunc-init.h
new file mode 100644
index 0000000..59d5ac6
--- /dev/null
+++ b/sysdeps/generic/ifunc-init.h
@@ -0,0 +1,54 @@ 
+/* IFUNC generic definitions.
+   This file is part of the GNU C Library.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+   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/>.  */
+
+/* These macros are used to implement ifunc selection in C.  To implement
+   an ifunc function, foo, which returns the address of __foo_impl1 or
+   __foo_impl2:
+
+   #define foo __redirect_foo
+   #include <foo.h>
+   #undef foo
+   #define SYMBOL_NAME foo
+   #include <ifunc-init.h>
+
+   extern __typeof (REDIRECT_NAME) OPTIMIZE (impl1) attribute_hidden;
+   extern __typeof (REDIRECT_NAME) OPTIMIZE (impl2) attribute_hidden;
+
+   static inline void *
+   foo_selector (void)
+   {
+     if (condition)
+      return OPTIMIZE (impl2);
+
+     return OPTIMIZE (impl1);
+   }
+
+   libc_ifunc_redirected (__redirect_foo, foo, IFUNC_SELECTOR ());
+*/
+
+#define PASTER1(x,y)	x##_##y
+#define EVALUATOR1(x,y)	PASTER1 (x,y)
+#define PASTER2(x,y)	__##x##_##y
+#define EVALUATOR2(x,y)	PASTER2 (x,y)
+
+/* Basically set '__redirect_<symbol>' to use as type definition,
+   '__<symbol>_<variant>' as the optimized implementation and
+   '<symbol>_ifunc_selector' as the IFUNC selector.  */
+#define REDIRECT_NAME	EVALUATOR1 (__redirect, SYMBOL_NAME)
+#define OPTIMIZE(name)	EVALUATOR2 (SYMBOL_NAME, name)
+#define IFUNC_SELECTOR	EVALUATOR1 (SYMBOL_NAME, ifunc_selector)
diff --git a/sysdeps/x86/init-arch.h b/sysdeps/x86/init-arch.h
index 15d3f09..06a21cc 100644
--- a/sysdeps/x86/init-arch.h
+++ b/sysdeps/x86/init-arch.h
@@ -20,46 +20,7 @@ 
 #else
 # include <ldsodefs.h>
 #endif
-
-/* These macros are used to implement ifunc selection in C.  To implement
-   an ifunc function, foo, which returns the address of __foo_sse2 or
-   __foo_avx2:
-
-   #define foo __redirect_foo
-   #define __foo __redirect___foo
-   #include <foo.h>
-   #undef foo
-   #undef __foo
-   #define SYMBOL_NAME foo
-   #include <init-arch.h>
-
-   extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
-   extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
-
-   static inline void *
-   foo_selector (void)
-   {
-     if (use AVX2)
-      return OPTIMIZE (avx2);
-
-     return OPTIMIZE (sse2);
-   }
-
-   libc_ifunc_redirected (__redirect_foo, foo, foo_selector ());
-
-*/
-
-#define PASTER1(x,y)	x##_##y
-#define EVALUATOR1(x,y)	PASTER1 (x,y)
-#define PASTER2(x,y)	__##x##_##y
-#define EVALUATOR2(x,y)	PASTER2 (x,y)
-
-/* Basically set '__redirect_<symbol>' to use as type definition,
-   '__<symbol>_<variant>' as the optimized implementation and
-   '<symbol>_ifunc_selector' as the IFUNC selector.  */
-#define REDIRECT_NAME	EVALUATOR1 (__redirect, SYMBOL_NAME)
-#define OPTIMIZE(name)	EVALUATOR2 (SYMBOL_NAME, name)
-#define IFUNC_SELECTOR	EVALUATOR1 (SYMBOL_NAME, ifunc_selector)
+#include <ifunc-init.h>
 
 #ifndef __x86_64__
 /* Due to the reordering and the other nifty extensions in i686, it is