allow to override PKGFORMAT when running make
building installation sets takes a long time, and is a .PHONY action.
Having a way to skip that when running make is esp. useful with IDEs
that have no nice way of separating the "run/debug" action from the
build action. (XCode, looking at you and your awkward schemes…)
Use with »make build PKGFORMAT=""«
Change-Id: Iab0c03a4096fe5571a5496b52504b3393e9f3cf6
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/137111
Tested-by: Jenkins
Reviewed-by: Christian Lohmaier <lohmaier+LibreOffice@googlemail.com>