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: Ic40abef2188ad4aa3a6c23a6d5729252f272f25e