This adds a suite of unit tests for libsigrok. It uses the 'Check'
tool/library (apt-get install check) to run the tests.
The configure tool tries to find libcheck. If it succeeds, a
"make check" will run all tests. Otherwise, none of the tests will
be built and "make check" will not run any tests.
This also means that users who don't have 'check' installed will still
be able to build and install libsigrok just fine.
We'll have a libsigrok and a libsigrokdecode release soon. After that,
any API changes must be properly documented and reflected in the
SO version (and package version) numbers of the libs.
Use SR_API to mark public API symbols, and SR_PRIV for private symbols.
Variables and functions marked 'static' are private already and don't
need SR_PRIV. However, functions which are not static (because they need
to be used in other libsigrok-internal files) but are also not meant to
be part of the public libsigrok API, must use SR_PRIV.
This uses the 'visibility' feature of gcc (requires gcc >= 4.0).
Details: http://gcc.gnu.org/wiki/Visibility
Uwe Hermann
Bert Vermeulen
Håvard Espeland