readme: greatly improve setup doc

Based upon what I have been using locally for a while now.

README.md

@@ -89,26 +89,99 @@ private key. To force signing with your own OpenPGP identity or key fingerprint
 add the below to `~/.devscripts`.
 
 ```shell
+DEBUILD_DPKG_BUILDPACKAGE_OPTS='-sa -i -I'
+DEBUILD_LINTIAN_OPTS='-i -I --show-overrides'
 DEBSIGN_MAINT='Firstname Lastname'
 ```
 
 ### cowbuilder / pbuilder
 
 Install `cowbuilder` and/or `pbuilder`, `cowbuilder` is recommended as it is
-more efficient.
+more efficient. Also install `eatmydata` to speed up building by disabling
+`fsync()` et al during building.
 
 Finally set the default build options and distribution in `/etc/pbuilderrc`.
 Option `-sa` forces creation of the source `.orig.tar.gz`.
 
 ```shell
 # Local
-DEBBUILDOPTS=-sa
+DEBBUILDOPTS='-sa -i -I'
 DISTRIBUTION=buster
+EATMYDATA=yes
+EXTRAPACKAGES=lintian
+HOOKDIR=/var/cache/pbuilder/hooks
+PDEBUILD_PBUILDER=cowbuilder
+```
+
+Now add hook files, so lintian runs after building and you get a shell when an
+errors occurs.
+
+File `/var/cache/pbuilder/hooks/B90lintian`
+
+```shell
+#!/bin/sh
+set -e
+apt-get -y --allow-downgrades install lintian
+echo "+++ lintian output +++"
+su -c "lintian -i -I --show-overrides /tmp/buildd/*.changes; :" -l pbuilder
+echo "+++ end of lintian output +++"
+```
+
+File `/var/cache/pbuilder/hooks/C10shell`
+
+```shell
+#!/bin/sh
+set -e
+apt-get -y --allow-downgrades install vim bash mc
+# invoke shell if build fails
+cd /tmp/buildd/*/debian/..
+/bin/bash < /dev/tty > /dev/tty 2> /dev/tty
 ```
 
 Run `sudo cowbuilder create` to build the initial rootfs. Later `sudo cowbuilder
 update` can keep it up-to-date. Refer to `cowbuilder(8)` for more details.
 
+### quilt
+
+The far majority of packages use the quilt utility to manage patches. In debian
+packages patches are stored under `debian/patches` instead of standard quilt's
+`patches`. Create `~/.quiltrc-dpkg`.
+
+```shell
+d=.
+while [ ! -d $d/debian -a `readlink -e $d` != / ];
+    do d=$d/..; done
+if [ -d $d/debian ] && [ -z $QUILT_PATCHES ]; then
+    # if in Debian packaging tree with unset $QUILT_PATCHES
+    QUILT_PATCHES="debian/patches"
+    QUILT_PATCH_OPTS="--reject-format=unified"
+    QUILT_DIFF_ARGS="-p ab --no-timestamps --no-index --color=auto"
+    QUILT_REFRESH_ARGS="-p ab --no-timestamps --no-index"
+    QUILT_COLORS="diff_hdr=1;32:diff_add=1;34:diff_rem=1;31:diff_hunk=1;33:diff_ctx=35:diff_cctx=33"
+    if ! [ -d $d/debian/patches ]; then mkdir $d/debian/patches; fi
+fi
+```
+
+Finally, create an alias in your shell rc.
+
+```shell
+alias dquilt="quilt --quiltrc=${HOME}/.quiltrc-dpkg"
+# note: zsh does not require the below complete line
+complete -F _quilt_completion $_quilt_complete_opt dquilt
+```
+
+### git-buildpackage
+
+Many packages that are maintained in git use git-buildpackage to automate common
+task. Usually per-package configuration is stored in `debian/gbp.conf`. Because
+we use pbuilder/cowbuilder create the `~/.gbp.conf` with the following contents.
+
+```shell
+[DEFAULT]
+builder = git-pbuilder -sa -i -I
+color = auto
+```
+
 ### reprepro
 
 Configuration of `reprepro` is not needed, as it is included in this repository
@@ -133,7 +206,8 @@ tarball. For example `uscan --download-current-version`.
 ### Modifying the package
 
 Do whatever needs to be done. For patches specifically, usually the easiest way
-it to use change sources in-tree and run `dpkg-source --commit`.
+it to use change sources in-tree and run `dpkg-source --commit`. You can also
+use (d)quilt directly.
 
 ### Bumping the package version
 
@@ -177,11 +251,11 @@ Building is as easy as running `sudo cowbuilder build sourcepkg.dsc`. For
 cowbuilder/pbuilder specifically the result will end up in
 `/var/cache/pbuilder/result`.
 
-Sign the binary package by running `debsign` on the `.changes` file.
+Sign the binary package by running `sign.sh`, included in this repository.
 
 ### Adding the packages to the repo
 
-Simply run `reprepro include binarypkg.changes`
+Simply run `include.sh`, included in this repository.
 
 Finally run `rsync.sh` to sync the local repository to the archive on
 https://mel.vin/debian/. Note that syncing is a primitive sync and not additive!
@@ -189,6 +263,10 @@ This means managing the actual repo should be done from a single machine, or by
 syncing the `db`, `dists` and `pool` folders. A more serious repo uses incoming
 queues which does not have this problem.
 
+To clear the locally built packages run `result_clear.sh`. Note that you need to
+`chown root:$USER` and `chmod 775` the result directory locally to avoid needing
+root to remove the built packages.
+
 ## Submitting patches upstream
 
 If the fix is proper and for a legitimate issue that exists in an official