Ship code coverage autoconf macros in dist tarball

This will enable code coverage for releases as well (install
autoconf-archive into the release tarball build environment for that),
and avoids incompatibilities between the version installed on the target
system and release build system.

Provide a dummy fallback for the Alpine and CentOS CI containers.

Fixes #91

autogen.sh

@@ -27,6 +27,12 @@ else
     echo 'EXTRA_DIST =' > docs/gtk-doc.make
 fi
 
+ax_coverage="$(aclocal --print)/ax_code_coverage.m4"
+if ! cp --verbose "$ax_coverage" m4; then
+    echo "ax_code_coverage.m4 (from autoconf-archive) not available, using dummy"
+    echo 'AC_DEFUN([AX_CODE_COVERAGE],[[CODE_COVERAGE_RULES=''] AC_SUBST([CODE_COVERAGE_RULES])])' > m4/ax_code_coverage.m4
+fi
+
 if type lcov >/dev/null 2>&1; then
     args="$args --enable-code-coverage"
 else

configure.ac

@@ -84,15 +84,7 @@ AC_CHECK_PROGS(VALAC, [valac])
 AM_PROG_VALAC([0.16.1])
 
 # code coverage support
-AC_MSG_CHECKING(for GNOME code coverage support)
-m4_ifdef([AX_CODE_COVERAGE],
-         [AC_MSG_RESULT(yes)
-          AX_CODE_COVERAGE],
-         [AC_MSG_RESULT(no)
-          CODE_COVERAGE_RULES=''
-          AC_SUBST([CODE_COVERAGE_RULES])
-          enable_code_coverage="no"])
-
+AX_CODE_COVERAGE
 CPPFLAGS="$CPPFLAGS $CODE_COVERAGE_CPPFLAGS"
 CFLAGS="$CFLAGS $CODE_COVERAGE_CFLAGS"
 LDFLAGS="$LDFLAGS $CODE_COVERAGE_LIBS"

tests/run-ubuntu-chroot

@@ -49,7 +49,7 @@ if [ -n "${PROPOSED:-}" ]; then
 fi
 apt-get update
 $UPGRADE
-apt-get install -y pkg-config dh-autoreconf valac libglib2.0-dev libudev-dev libgudev-1.0-dev python3-gi gobject-introspection libgirepository1.0-dev gir1.2-glib-2.0 gir1.2-gudev-1.0 gtk-doc-tools udev xserver-xorg-video-dummy xserver-xorg-input-evdev xserver-xorg-input-synaptics xinput usbutils gphoto2 valgrind
+apt-get install -y pkg-config dh-autoreconf autoconf-archive valac libglib2.0-dev libudev-dev libgudev-1.0-dev python3-gi gobject-introspection libgirepository1.0-dev gir1.2-glib-2.0 gir1.2-gudev-1.0 gtk-doc-tools udev xserver-xorg-video-dummy xserver-xorg-input-evdev xserver-xorg-input-synaptics xinput usbutils gphoto2 valgrind
 
 # run build and tests as user
 chown -R buildd:buildd /build