Documentation/Changes: perl is needed to build the kernel

Perl is used on the kernel Makefile to generate documentation, firmwares
in c source form, sources, graphs, and some headers and this fact is
undocumented.

[akpm@linux-foundation.org: 80-columns, please]
Signed-off-by: NJose Luis Perez Diez <jluis@escomposlinux.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Documentation/Changes

@@ -72,6 +72,13 @@ assembling the 16-bit boot code, removing the need for as86 to compile
 your kernel.  This change does, however, mean that you need a recent
 release of binutils.
 
+Perl
+----
+
+You will need perl 5 and the following modules: Getopt::Long, Getopt::Std,
+File::Basename, and File::Find to build the kernel.
+
+
 System utilities
 ================