Introduce the HAVE_SERIAL_COMM identifier, which gets derived from, but
need not be identical to the HAVE_LIBSERIALPORT condition.
Derive the NEED_SERIAL automake condition from the general availability
of serial communication not the specific libserialport library.
Adjust source code references. Stick with HAVE_LIBSERIALPORT where the
specific library is meant, but switch to HAVE_SERIAL_COMM where the
availability of serial communication in general is meant.
Since Autoconf places some important feature flags only into the
configuration header, it is necessary to include it globally to
guarantee a consistent build.
Move the include flags for files in the source tree from
configure.ac to Makefile.am where they belong. Also use
AM_CPPFLAGS instead of CFLAGS/CXXFLAGS to make sure the
files in the build/source tree are always picked up first.
Also, remove the include/libsigrok sub-directory from the
search path, thereby making the <libsigrok/> prefix mandatory
when building libsigrok itself. This matches the convention
already imposed on users of the library.
Gerhard Sittig
Daniel Elstner
Uwe Hermann
Aurelien Jacobs