This file tries to document how the `mkpatch' program works.The file in copyright (c) 1999 by Frodo Looijaardmkpatch compares the newest I2C 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 I2C sources.mkpatch needs two arguments. The first is the root of the I2C package,the second is the root of Linux kernel tree. For example:  cd /tmp/i2c-1.0.0  mkpatch/mkpatch . /usr/src/linuxThe 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/i2c-diffsLater on, you will want to apply the diffs:  cd /usr/src/linuc  patch -p1 -E < /tmp/i2c-diffsOf course, this can be combined:  mkpatch/mkpatch . /usr/src/linux | patch -d /usr/src/linux -p1 -Emkpatch uses several files in the mkpatch subdirectory. The location ofthese files is hardcoded in the program, but all other files used arespecified 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 I2C package root) of the I2C 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 I2C files in     FILES, before the normal diff is generated. This allow us to use    `#include "i2c.h"' when compiling in the package tree, and    `#include <linux/i2c.h>' in the kernel tree.  OLDI2C    The generated kernel diffs will rename the old I2C header file to    `i2c-old'. In the files specified in this file, `#include' statements    will be changed accordingly.  Makefile, Config.in    These files are new and will be copied to the appropriate place as    specified in FILES.mkpatch does several things:  * It generates diffs to change `#include <linux/i2c.h>' to     `#include <linux/i2c-old.h>' for files mentioned in OLDI2C  * 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    I2C file as specified in INCLUDES, and it takes care of    lm_sensors changes.  * It handles several special files, that have to be scanned explicitly    to generate diffs to for themThe generated diffs have specific headers. It will seem as if the oldkernel was contained in the `linux-old' directory, and the new patchedkernel in the `linux' directory, regardless of where the kernel wasactually located.Most intricate are the special files that are handled. These specialfiles were already present in the kernel, but had to be patched. Becausethey can change between kernel versions, I had to scan them by hand tofind where the new code should be inserted. Each file has documentedwhat actually happens.Sometimes, a new file is inserted in the kernel tree by the I2C package,and it needs to be patched by the lm_sensors package. In that case, thepart that is patched by the lm_sensors package is specifically marked.If not, the I2C package would back out the lm_sensors changes!The markers are:  sensors code starts here  sensors code ends hereThey may be anywhere on a line, and must always occur in pairs.More than one pair may be present.