They're not too useful as they mostly consist of a list of function names,
and that list is already available in the respective struct. The wiki
API docs and the code in the various hardware/output drivers serve as
useful examples already, no need for additional files.
We should use these (internal) functions in libsigrok exclusively from
now on, i.e. no more use of glib's g_debug() etc.
These functions are only for libsigrok, the frontends use whatever
logging mechanism is suitable there.
Until now the build would break if the user doesn't enable at least one
of the libusb1.0-based LAs. I.e., you could not compile only OLS, or
only the demo driver.
Use libtool "noinst" local helper libs and use one Makefile.am per
subdir, which is the usual/preferred method. These helper libraries are
purely local and will not be installed.
This also fixes out-of-tree builds of sigrok, i.e. building in a
directory other than the sigrok source directory, e.g.
$ cd /home/user
$ git clone ...sigrok
$ cd sigrok
$ ./autogen.sh
$ mkdir /tmp/foo
$ cd /tmp/foo
$ /home/user/sigrok/configure
$ make
$ make install
This will place all build results (.o files, .la files, etc) in the
local build directory (/tmp/foo) instead of the source directory
(/home/user/sigrok in this example). The installation directory is
selected via the --prefix configure option (/usr/local per default).