netplug: add two patches to fix musl build issues

netplug: add two patches to fix musl build issues

This commit adds two patches to netplug that are needed for this package
to build with musl:

 - One patch to add a missing header inclusion
 - One patch to fix a conflicting prototype on __assert_fail().

Fixes:

  http://autobuild.buildroot.net/results/c2a5dfedba46cc8eb3d0c5c43f1f76fe0bb1805f/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by:  "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>