Arm32 dynamic function dispatch

Test: Run bionic unit test.
Test: Use gdb to make sure the right function is selected.

Change-Id: I34ccd83d472c13993f75672b1aac2b2eae65c499
diff --git a/libc/arch-arm/krait/bionic/memcpy.S b/libc/arch-arm/krait/bionic/memcpy.S
index 49fd040..6618b3a 100644
--- a/libc/arch-arm/krait/bionic/memcpy.S
+++ b/libc/arch-arm/krait/bionic/memcpy.S
@@ -42,7 +42,7 @@
         .thumb
         .thumb_func
 
-ENTRY(__memcpy)
+ENTRY(__memcpy_krait)
         pld     [r1, #64]
         stmfd   sp!, {r0, lr}
         .cfi_adjust_cfa_offset 8
@@ -50,4 +50,4 @@
         .cfi_rel_offset lr, 4
 
 #include "memcpy_base.S"
-END(__memcpy)
+END(__memcpy_krait)