crtools: Take MINCORE_ANON pages into account

Reduce the pages-xxx.img file size significantly (from 2.1M to ~100K for simple counter test)
by not dumping private file pages, that have not yet changed from its file prototype.

If you'll have problems with it, just let me know and comment the definition of PAGE_ANON not
to block your work.

This uses the implemented earlier flag from mincore.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

include/image.h

@@ -17,6 +17,7 @@
 
 #define PAGE_IMAGE_SIZE	4096
 #define PAGE_RSS	1
+#define PAGE_ANON	2
 
 struct fdinfo_entry {
 	u8	type;

parasite.c

@@ -78,7 +78,17 @@ static void sys_write_msg(const char *msg)
 
 static inline int should_dump_page(struct vma_entry *vmae, unsigned char mincore_flags)
 {
+#ifdef PAGE_ANON
+	if (vma_entry_is(vmae, VMA_DUMP_ALL))
+		return 1;
+
+	if (vma_entry_is(vmae, VMA_FILE_PRIVATE))
+		return mincore_flags & PAGE_ANON;
+	else
+		return mincore_flags & PAGE_RSS;
+#else
 	return (mincore_flags & PAGE_RSS) || vma_entry_is(vmae, VMA_DUMP_ALL);
+#endif
 }
 
 /*