Count "virtual" packages seperately in total in build-matrix.html

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Use absolute path for $(TOP_DIR)

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Add git-init-% target that initializes a temporary Git repo for patch workflow

Fixes #134.

Signed-off-by: Timothy Gu <timothygu99@gmail.com>