Individual libraries' `target_h` stub headers have now all been moved
from `mbed-headers-base` to `mbed-headers-<library>`.
Note: Even though headers previously in `target_h` are technically
stubs/fakes too, they are used by not only unit tests but also regular
libraries when compiled for unit tests, because no target-specific HAL
implementation exists in this case. In order for regular library
sources to pick up `target_h` headers, those headers must
* have the same names as regular headers
* appear first in include paths
This is why those headers are part of `mbed-headers-<library>` and not
`mbed-stubs-<library>`. Before this refactoring, `mbed-headers-base`
was the first in unit tests' include paths.
The header `mbed.h` pulls in headers from a number of Mbed OS
components that are not necessarily used. It was intended for user
applications only, and libraries and unit tests should explicitly
include library headers it uses to limit dependencies.
This change avoids having to link unnecessary libraries in storage
unit tests' CMake definitions.
Move storage stubs from UNITTESTS/stubs into components inside the
top-level storage directory. Specifically,
* storage/blockdevice/tests/UNITTESTS/doubles/ for BlockDevice stubs.
* storage/kvstore/filesystemstore/tests/UNITTESTS/ for a stub used by
the FileSystemStore test. The stub has been renamed from
kv_config_stub.cpp to filesystemstore_kv_config_stub.cpp, to make it
evident why it doesn't go into storage/kvstore/kv_config/.