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/sigsetjmp.S b/libc/arch-arm/bionic/sigsetjmp.S
index 50e6429..12311e5 100644
--- a/libc/arch-arm/bionic/sigsetjmp.S
+++ b/libc/arch-arm/bionic/sigsetjmp.S
@@ -33,6 +33,8 @@
  * SUCH DAMAGE.
  */
 
+#define _ALIGN_TEXT .align 0
+
 #include <machine/asm.h>
 #include <machine/setjmp.h>
 
@@ -50,6 +52,7 @@
 	teq	r1, #0
 	beq	PIC_SYM(_C_LABEL(_setjmp), PLT)
 	b	PIC_SYM(_C_LABEL(setjmp), PLT)
+END(sigsetjmp)
 
 .L_setjmp_magic:
 	.word	_JB_MAGIC__SETJMP
@@ -60,3 +63,4 @@
 	teq	r2, r3
 	beq	PIC_SYM(_C_LABEL(_longjmp), PLT)
 	b	PIC_SYM(_C_LABEL(longjmp), PLT)
+END(siglongjmp)