Add vendor_available:true to libpng

Bug: 38244611
Test: build sailfish
Merged-In: Idb557320141a95347989d6403bb9d1b6a4af7954
Change-Id: If514202184e125742a3205052f06a84d2195525d
(cherry picked from commit bdd08fcdde23b142e4272de23c7c2b4339b0e102)
1 file changed