package/vlc: Fix strerror_l related compile error

strerror_l is not implemented by uClibc.

Fixes
http://autobuild.buildroot.net/results/ae3/ae31f4585d2c2f850473c446f1ccfba7699c711b/
http://autobuild.buildroot.net/results/504/504cf78a08315e2fc6eaeb9a29ae791972753830/
http://autobuild.buildroot.net/results/092/09280c5d63da9b8b58916c32e6040a98f7ff0ee8/
http://autobuild.buildroot.net/results/da6/da62d97ea060ce03db94f59a91d84a235d03e8f0/
http://autobuild.buildroot.net/results/7a4/7a40f66b3be8cd71a27df04415c4851cd4426cc3/



Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>