add comments about magic numbers

diff --git a/include/elf/common.h b/include/elf/common.h
index 3c3ed7e1b69bf3bb5d0f03a7558d1a816360109d..c93295a49d892a7ccc5f25e1ceb5c8c3535b0160 100644 (file)
--- a/include/elf/common.h
+++ b/include/elf/common.h
@@ -92,7 +92,11 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
 
 /* If it is necessary to assign new unofficial EM_* values, please pick large
    random numbers (0x8523, 0xa7f2, etc.) to minimize the chances of collision
-   with official or non-GNU unofficial values.  */
+   with official or non-GNU unofficial values.
+
+   NOTE: Do not just increment the most recent number by one.
+   Somebody else somewhere will do exactly the same thing, and you
+   will have a collision.  Instead, pick a random number.  */
 
 /* Cygnus PowerPC ELF backend.  Written in the absence of an ABI.  */
 #define EM_CYGNUS_POWERPC 0x9025
@@ -113,6 +117,8 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
 #define EM_CYGNUS_D10V 0x9027
 /* end-sanitize-d10v */
 
+/* See the above comment before you add a new EM_* value here.  */
+
 /* Values for e_version */
 
 #define EV_NONE                0               /* Invalid ELF version */