Script to build-in used modules, based on streamline_config.pl

Script to build-in used modules, based on streamline_config.pl

[Phil Endecott]

Dear List,

Last month, Steven Rostedt posted a script to disable 
not-currently-used modules from your .config:

   http://article.gmane.org/gmane.linux.kernel/734536

It works by parsing the kernel Makefiles to build a map from module 
names to config settings.

I've made a slightly modified version of this that takes the .config 
for an all-modular kernel (e.g. a distribution kernel) and changes the 
settings for those modules that are currently loaded so that they will 
be built in:

   http://chezphil.org/tmp/buildin_used_mods.pl

The aim of this is to provide a semi-automatic method to produce a 
custom kernel that has everything needed for your hardware built in, so 
you don't need an initrd.

One issue that I encountered is that not every config setting builds a 
module and may not be changed.  For example, if I need module xyz to 
support my IDE disk, then the script will change CONFIG_XYZ from m to 
y.  However, it won't change CONFIG_IDE from m to y.  When I 
subsequently make menuconfig, it detects that CONFIG_XYZ=y is 
incompatible with CONFIG_IDE=m, but it fixes it in the wrong way; it 
changes CONFIG_XYZ back to m, rather than changing CONFIG_IDE to y.  Is 
there any way to change this?

Someone with better Perl skills than me could probably merge Steven's 
original script with my variation with a command-line option to 
determine the behaviour.  It would be good to something like this merged.

Cheers,  Phil.