alignof, array_size, crc: provide comments to allow testing examples.

ccan/alignof/_info

@@ -19,10 +19,13 @@
  *	#include <stdlib.h>
  *	#include <ccan/alignof/alignof.h>
  *
+ *	// Output contains "ALIGNOF(char) == 1"
+ *	// Will also print out whether an onstack char array can hold a long.
  *	int main(int argc, char *argv[])
  *	{
  *		char arr[sizeof(int)];
  *
+ *		printf("ALIGNOF(char) == %zu\n", ALIGNOF(char));
  *		if ((unsigned long)arr % ALIGNOF(int)) {
  *			printf("arr %p CANNOT hold an int\n", arr);
  *			exit(1);

ccan/array_size/_info

@@ -12,17 +12,21 @@
  * macro or constant.
  *
  * Example:
+ *	// Outputs "Initialized 32 values"
  *	#include <ccan/array_size/array_size.h>
  *	#include <stdlib.h>
+ *	#include <stdio.h>
  *
  *	// We currently use 32 random values.
  *	static unsigned int vals[32];
  *
- *	static void init_values(void)
+ *	int main(void)
  *	{
  *		unsigned int i;
  *		for (i = 0; i < ARRAY_SIZE(vals); i++)
  *			vals[i] = random();
+ *		printf("Initialized %u values\n", i);
+ *		return 0;
  *	}
  *
  * License: LGPL (2 or any later version)

ccan/crc/_info

@@ -15,6 +15,7 @@
  *	#include <stdio.h>
  *	#include <stdlib.h>
  *
+ *	// Given IHATEMATH outputs 0x98a3b8df
  *	int main(int argc, char *argv[])
  *	{
  *		if (argc != 2) {