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-strcpy-slm.S b/libc/arch-x86/silvermont/string/sse2-strcpy-slm.S
index b5d84b5..22ceeab 100755
--- a/libc/arch-x86/silvermont/string/sse2-strcpy-slm.S
+++ b/libc/arch-x86/silvermont/string/sse2-strcpy-slm.S
@@ -79,7 +79,7 @@
 #define POP(REG) popl REG; CFI_POP (REG)
 
 #ifndef STRCPY
-# define STRCPY  strcpy
+# define STRCPY  strcpy_generic
 #endif
 
 #ifdef USE_AS_STPNCPY