[glib] grand: Document this is not for cryptographic purposes

[Colin Walters <walters src gnome org>]

commit 1e1e2d1ff7debb3941a8841c4ec501dbd6edd1fd
Author: Colin Walters <walters verbum org>
Date:   Wed Oct 23 16:41:09 2013 -0400

    grand: Document this is not for cryptographic purposes
    
    While this is obvious to seasoned experts upon inspection, it is
    really worth documenting explicitly.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=710736

 glib/grand.c |   20 ++++++++++++++++----
 1 files changed, 16 insertions(+), 4 deletions(-)
---
diff --git a/glib/grand.c b/glib/grand.c
index 1485c2e..9b2c0f8 100644
--- a/glib/grand.c
+++ b/glib/grand.c
@@ -65,10 +65,22 @@
  * @short_description: pseudo-random number generator
  *
  * The following functions allow you to use a portable, fast and good
- * pseudo-random number generator (PRNG). It uses the Mersenne Twister
- * PRNG, which was originally developed by Makoto Matsumoto and Takuji
- * Nishimura. Further information can be found at
- * <ulink url="http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html";>
+ * pseudo-random number generator (PRNG).
+ * 
+ * <warning><para>Do not use this API for cryptographic purposes such as key
+ * generation, nonces, salts or one-time pads.</para></warning>
+ *
+ * This PRNG is suitable for non-cryptographic use such as in games
+ * (shuffling a card deck, generating levels), generating data for a
+ * test suite, etc. If you need random data for cryptographic
+ * purposes, it is recommended to use platform-specific APIs such as
+ * <literal>/dev/random</literal> on Unix, or CryptGenRandom() on
+ * Windows.
+ *
+ * GRand uses the Mersenne Twister PRNG, which was originally
+ * developed by Makoto Matsumoto and Takuji Nishimura. Further
+ * information can be found at <ulink
+ * url="http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html";>
  * http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html</ulink>.
  *
  * If you just need a random number, you simply call the