Use ifunc to dynamically dispatch libc routines for x86

Test: run bionic unit test in aosp_cf_x86_phone emulator
Change-Id: Ib0c0de37cd38d24bfce2dfbe35b8fd8edff004af
diff --git a/libc/arch-x86/atom/string/ssse3-memcpy-atom.S b/libc/arch-x86/atom/string/ssse3-memcpy-atom.S
index 2b3b7a5..fa67188 100644
--- a/libc/arch-x86/atom/string/ssse3-memcpy-atom.S
+++ b/libc/arch-x86/atom/string/ssse3-memcpy-atom.S
@@ -31,7 +31,7 @@
 #include "cache.h"
 
 #ifndef MEMCPY
-# define MEMCPY	memcpy
+# define MEMCPY	memcpy_atom
 #endif
 
 #ifndef USE_AS_MEMMOVE
@@ -3133,4 +3133,4 @@
 
 END (MEMCPY)
 
-ALIAS_SYMBOL(memmove, MEMCPY)
+ALIAS_SYMBOL(memmove_atom, MEMCPY)