gdb/

PR 11804
	* defs.h (find_memory_region_ftype): New comment.  New arg modified.
	* fbsd-nat.c (fbsd_find_memory_regions): Add the passed modified value.
	* gcore.c (gcore_create_callback): New function comment.  Add modified
	parameter.  Only write modified regions.  Set SEC_READONLY exactly
	according to MODIFIED.
	(objfile_find_memory_regions): Ignore separate debug info files.  Ass
	the passed modified value to FUNC.
	* gnu-nat.c (gnu_find_memory_regions): Add the passed modified value.
	* linux-tdep.c (linux_find_memory_regions): Try to reads smaps file
	first.  New variables modified and has_anonymous.  Parse the lines of
	smaps file.  Add the passed MODIFIED value to FUNC.
	* procfs.c (find_memory_regions_callback): Add the passed modified
	value.

gdb/testsuite/
	PR 11804
	* gdb.base/gcore-relro.exp: New file.
	* gdb.base/gcore-relro-main.c: New file.
	* gdb.base/gcore-relro-lib.c: New file.

gdb/procfs.c

@@ -5074,6 +5074,7 @@ find_memory_regions_callback (struct prmap *map,
 		  (map->pr_mflags & MA_READ) != 0,
 		  (map->pr_mflags & MA_WRITE) != 0,
 		  (map->pr_mflags & MA_EXEC) != 0,
+		  1, /* MODIFIED is unknown, pass it as true.  */
 		  data);
 }