mkpatch documentation, both as a separate /doc file and in the

script itself. And a minor typo fix in Config.in


git-svn-id: http://lm-sensors.org/svn/lm-sensors/trunk@549 7894878c-1315-0410-8ee3-d5d059ff63e0

doc/mkpatch

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+This file tries to document how the `mkpatch' program works.
+The file in copyright (c) 1999 by Frodo Looijaard
+
+mkpatch compares the newest lm_sensors sources with what is found in a kernel,
+and generates a set of diffs. These diffs can be amplied to that kernel,
+after which the kernel is synchronised with the current lm_sensors sources.
+
+You should always run mkpatch against a kernel tree that has been patched
+for the newest I2C sources.
+
+mkpatch needs two arguments. The first is the root of the lm_sensors package,
+the second is the root of Linux kernel tree. For example:
+  cd /tmp/lm_sensors-2.4.0
+  mkpatch/mkpatch . /usr/src/linux
+The patch file is written to stdout; any errors are written to stderr.
+So you will want to capture the output:
+  mkpatch/mkpatch . /usr/src/linux > /tmp/lm_sensors-diffs
+Later on, you will want to apply the diffs:
+  cd /usr/src/linuc
+  patch -p1 -E < /tmp/lm_sensors-diffs
+Of course, this can be combined:
+  mkpatch/mkpatch . /usr/src/linux | patch -d /usr/src/linux -p1 -E
+
+mkpatch uses several files in the mkpatch subdirectory. The location of
+these files is hardcoded in the program, but all other files used are
+specified in these files, and can easily be changed. Used files are:
+  FILES
+    a list of files that will be considered by mkpatch. Each line contains
+    two filenames, separated by whitespace. The first is the name and
+    location (relative to the lm_sensors package root) of the lm_sensors 
+    file, the second is the name and location (relative to the kernel root) of 
+    the kernel file. A diff will be created between these two files.
+  INCLUDES
+    A list of include file changes. Each line contains two strings that
+    can be found after a `#include' statement. All occurences of the
+    first string will be changed to the second, for all lm_sensors files in 
+    FILES, before the normal diff is generated. This allow us to use
+    `#include "sensors.h"' when compiling in the package tree, and
+    `#include <linux/sensors.h>' in the kernel tree.
+  Makefile, Config.in
+    These files are new and will be copied to the appropriate place as
+    specified in FILES.
+
+mkpatch does several things:
+  * For each file pair as specified in FILES, it creates a diff between
+    them, but before that is done, it changes `#include' lines in the
+    lm_sensors file as specified in INCLUDES
+  * It handles several special files, that have to be scanned explicitely
+    to generate diffs to for them
+
+The generated diffs have specific headers. It will seem as if the old
+kernel was contained in the `linux-old' directory, and the new patched
+kernel in the `linux' directory, regardless of where the kernel was
+actually located.
+
+Most intricate are the special files that are handled. These special
+files were already present in the kernel, but had to be patched. Because
+they can change between kernel versions, I had to scan them by hand to
+find where the new code should be inserted. Each file has documented
+what actually happens.