--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2011-09-08  Reuben Thomas  <rrt@sc3d.org>
+            Bruno Haible  <bruno@clisp.org>
+
+	Doc about crypt functions.
+	* doc/posix-functions/crypt.texi: Mention need for _GNU_SOURCE on glibc
+	systems.
+	* doc/posix-functions/encrypt.texi: Likewise.
+	* doc/posix-functions/setkey.texi: Likewise.
+
 2011-09-08  Simon Josefsson  <simon@josefsson.org>
 
 	* lib/gc.h: Fix copyright header.

--- a/doc/posix-functions/crypt.texi
+++ b/doc/posix-functions/crypt.texi
@@ -15,4 +15,8 @@
 @item
 This function is missing on some platforms:
 FreeBSD 6.0, NetBSD 5.0, Cygwin, mingw.
+@item
+This function is not declared in @code{<unistd.h>}
+(without @code{-D_GNU_SOURCE}) on some platforms:
+glibc 2.11.
 @end itemize

--- a/doc/posix-functions/encrypt.texi
+++ b/doc/posix-functions/encrypt.texi
@@ -15,4 +15,8 @@
 @item
 This function is missing on some platforms:
 NetBSD 5.0, Minix 3.1.8, Cygwin, mingw, BeOS.
+@item
+This function is not declared in @code{<unistd.h>}
+(without @code{-D_GNU_SOURCE}) on some platforms:
+glibc 2.11.
 @end itemize

--- a/doc/posix-functions/setkey.texi
+++ b/doc/posix-functions/setkey.texi
@@ -15,4 +15,8 @@
 @item
 This function is missing on some platforms:
 NetBSD 5.0, Minix 3.1.8, Cygwin, mingw, BeOS.
+@item
+This function is not declared in @code{<stdlib.h>}
+(without @code{-D_GNU_SOURCE}) on some platforms:
+glibc 2.11.
 @end itemize