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/generic/string/strcmp.S b/libc/arch-x86/generic/string/strcmp.S
index 580f4d5..7b003e8 100644
--- a/libc/arch-x86/generic/string/strcmp.S
+++ b/libc/arch-x86/generic/string/strcmp.S
@@ -12,7 +12,7 @@
  * cache.
  */
 
-ENTRY(strcmp)
+ENTRY(strcmp_generic)
 	movl	0x04(%esp),%eax
 	movl	0x08(%esp),%edx
 	jmp	L2			/* Jump into the loop! */
@@ -79,4 +79,4 @@
 	movzbl	(%edx),%edx
 	subl	%edx,%eax
 	ret
-END(strcmp)
+END(strcmp_generic)