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/silvermont/string/sse2-memmove-slm.S b/libc/arch-x86/silvermont/string/sse2-memmove-slm.S
index ceada1b..48087d8 100644
--- a/libc/arch-x86/silvermont/string/sse2-memmove-slm.S
+++ b/libc/arch-x86/silvermont/string/sse2-memmove-slm.S
@@ -31,7 +31,7 @@
 #include "cache.h"
 
 #ifndef MEMMOVE
-# define MEMMOVE	memmove
+# define MEMMOVE	memmove_generic
 #endif
 
 #ifndef L
@@ -544,4 +544,4 @@
 
 END (MEMMOVE)
 
-ALIAS_SYMBOL(memcpy, MEMMOVE)
+ALIAS_SYMBOL(memcpy_generic, MEMMOVE)