Make int3 example in comments more cut-n-pastable

I found that I use it quite often. Lets make it so that
after cut-n-pasting it into a file, there is no need
to edit the result (e.g. no need to remove C comment
chars from every line.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

strace.c

@@ -1415,12 +1415,13 @@ test_ptrace_setoptions_followfork(void)
  *
  * Use of this option enables correct handling of user-generated SIGTRAPs,
  * and SIGTRAPs generated by special instructions such as int3 on x86:
- * _start:	.globl	_start
- *		int3
- *		movl	$42, %ebx
- *		movl	$1, %eax
- *		int	$0x80
- * (compile with: "gcc -nostartfiles -nostdlib -o int3 int3.S")
+
+# compile with: gcc -nostartfiles -nostdlib -o int3 int3.S
+_start:		.globl	_start
+		int3
+		movl	$42, %ebx
+		movl	$1, %eax
+		int	$0x80
  */
 static int
 test_ptrace_setoptions_for_all(void)