vendor + vendor_available modules built with BOARD_VNDK_VERSION :=
current aren't allowed to use global headers. Since libutils uses
system headers itself, it should export them as well.
Bug: 33241851
Test: building with BOARD_VNDK_VERSION := current produces many fewer
errors.
Change-Id: Icc7d2beb2a17da291434c6282eb1b9eb458f114c
Merged-In: I950821f1dae3ddc110db50869247913d5b1aa638
Bug: 33241851
Test: No changes for modules not using VNDK. For compiling with VNDK,
add libsystem_headers as dependency for using these headers
Change-Id: I1a8a44073424cc0db625e31d44cb16b78c5a9ca1
Merged-In: I2acce0ab771e10ac83461c2f931e2c19e922089e