Add function marks and size indications

Add a macro to annotate function end and start using both ENTRY and END
for each function. This allows valgrind (and presumably other debugging
tools) to use the debug symbols to trace the functions.

Change-Id: I5f09cef8e22fb356eb6f5cee952b031e567599b6
diff --git a/libc/arch-arm/bionic/strcpy.S b/libc/arch-arm/bionic/strcpy.S
index 70c353f..21dafda 100644
--- a/libc/arch-arm/bionic/strcpy.S
+++ b/libc/arch-arm/bionic/strcpy.S
@@ -30,15 +30,9 @@
  */
 
 #include <machine/cpu-features.h>
+#include <machine/asm.h>
 
-	.text
-
-	.global strcpy
-	.type strcpy, %function
-	.align 4
-
-strcpy:
-	.fnstart
+ENTRY(strcpy)
 	PLD(r1, #0)
 	eor	r2, r0, r1
 	mov	ip, r0
@@ -136,3 +130,4 @@
 	cmp	r2, #0
 	bne	4b
 	bx	lr
+END(strcpy)