build script is build.sh

Check that the username is valid before doing any work. Use the default regex from debian's adduser.conf. Will also avoid risk of special characters causing issues.

Allows essid and passwords with special characters.

Fix typo

Fixes #251

* Tidy up and simplify function code
* Allow to pass extra arguments to debootstrap, e.g. `--variant minbase`
* Preserve compatibility with existing function calls

* Allow to customise pi-gen script name and repository in the generated issue file
* Preserve compatibility with existing function calls

Fixes #253

Rather than use --env-file, which gets overwritten by the regular config file, pass the any arguments to build-docker.sh through to build.sh.

Give a friendly error message early.

When copying files to boot, options that are not supported on fat32 can cause errors. For example owner, group and xattrs.

Fixes #257 #104 #193

Instead of searching by full path, which is prone to fail, read full list and grep on filename.

* Made more specific shellcheck disables
* Fixed variable quoting (SC2086,SC2064)
* Use `$*` expansion instead of `$@` when not using arrays (SC2124)
* Use cleaner `$()` syntax instead of back quotes (SC2006)
* Improved comparator (SC2166)
* Minor improvements in coding style

Tested clean output using: `find -name "*.sh" | xargs -n1 shellcheck -x`.

Avoids a later failure with a less informative message. See #248

Fixes #264

raspberrypi/linux#2799

* SC1091: the `config` file might not be present, which is normal.
* SC2086: Double quote to prevent globbing and word splitting.

Tested clean output using: `find -name "*.sh" -exec shellcheck -x {} \;`

…280)

The `(..)/raspberrypi-kernel/changelog.Debian.gz` file is not guaranteed
to be present in the built `ROOTFS_DIR`, for example when building very
minimal images without package documentation. In these cases, the `firmware`
variable will be left empty and the subsequent calls to `curl` will return
large 404 HTML content from GitHub.

Instead, simply check if the changelog file exists before using it.

Note that quotes are needed, see bug #288.

Remove ui and staging components

Add sdhci.debug_quirks2=4 to cmdline.txt when resizing

Only remove 'quiet' from cmdline if splash screen is off

Java 8 segfaults during install.
Installing OpenJDK 11 first prevents Java 8 from running.

This reverts commit 3682a74.

With the Qemu version shipped with Debian Stretch, the `man-db` package
being installed for Buster in the image triggers many of these errors:

    qemu: Unsupported syscall: 383

This is a manifestation of the following bug:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=891109

This is resolved in the current Qemu version shipped with Debian Buster.

Added a handy message to make it clear that compiling on a 64 bit OS is causing issues. After spending over an hour of troubleshooting think it should be made clearer as it'll affect quite a few users.