apply-patches.sh: add documentation

# -Erik

#

# (c) 2002 Erik Andersen <andersen@codepoet.org>

#

# Parameters:

# - the build directory, optional, default value is '.'. The place where are

# the package sources.

# - the patch directory, optional, default '../kernel-patches'. The place

# where are the scripts you want to apply.

# - other parameters are the patch name patterns, optional, default value is

# '*'. Pattern(s) describing the patch names you want to apply.

#

# The script will look recursively for patches from the patch directory. If a

# file is named 'series' then only patches mentionned into it will be applied.

# If not, the script will look for file names matching pattern(s). If the name

# ends with '.tar.*', '.tbz2' or '.tgz', the file is considered as an archive

# and will be uncompressed into a directory named

# '.patches-name_of_the_archive-unpacked'. It's the turn of this directory to

# be scanned with '*' as pattern. Remember that scanning is recursive. Other

# files than series file and archives are considered as a patch.

#

# Once a patch is found, the script will try to apply it. If its name doesn't

# end with '.gz', '.bz', '.bz2', '.zip', '.Z', '.diff*' or '.patch*', it will

# be skipped. If necessary, the patch will be uncompressed before being

# applied. The list of the patches applied is stored in '.applied_patches_list'

# file in the build directory.

# Set directories from arguments, or use defaults.

builddir=${1-.}