When the vndk is enabled (BOARD_VNDK_VERSION=current),
vendor libraries must only link against vendor variants
in the build system. This means that they receive restricted
sets of headers and that automatic global headers are restricted.
Test: build libqcomvoiceprocessingdescriptors with BOARD_VNDK_VERSION=current
Bug: 37342627
Change-Id: Ibef8462745a6c653fcb8b2298db6307c8502eace