argp-standalone: import package from packages.git

argp-standalone is required by elfutils, itself required by perf. So
we'll move this package from packages.git and make it part of the core
distribution.

Signed-off-by: Mathieu Olivari <mathieu@codeaurora.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@45967 3c298f89-4303-0410-b956-a3cf2f4a3e73