Add optimized 64 bit strcpy.

Change-Id: I4ac12735a53c3ae9336b148ce694fe6c63613139
diff --git a/libc/arch-arm64/generic-neon/generic-neon.mk b/libc/arch-arm64/generic-neon/generic-neon.mk
index 2cbe3cf..6a10fde 100644
--- a/libc/arch-arm64/generic-neon/generic-neon.mk
+++ b/libc/arch-arm64/generic-neon/generic-neon.mk
@@ -3,6 +3,7 @@
     arch-arm64/generic/bionic/memmove.S \
     arch-arm64/generic/bionic/memset.S \
     arch-arm64/generic/bionic/strcmp.S \
+    arch-arm64/generic/bionic/strcpy.S \
     arch-arm64/generic/bionic/strlen.S \
     arch-arm64/generic/bionic/strncmp.S \
     arch-arm64/generic/bionic/strnlen.S \