build-system: add libmtp for our Windows builds

This uses latest master (as that's the only one that has the explicit
Descent Mk2i support in it).

Right now, unfortunately the MXE build fails.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

packaging/windows/mxe-based-build.sh

@@ -153,6 +153,28 @@ if [ ! -f libdivecomputer/configure ] ; then
 	autoreconf --install
 fi
 
+# build libmtp as that isn't available via MXE
+cd "$BUILDDIR"
+if [[ ! -d libmtp || -f build.libmtp ]] ; then
+	rm -f build.libmtp
+	cd "$BASEDIR/libmtp"
+	export NOCONFIGURE=1
+	# crudely disable the interactive part of autogen.sh
+	sed --in-place=.bak 's/read IN/IN="N"/;s/echo "Auto/#echo "Auto/' autogen.sh
+	bash autogen.sh
+	mv autogen.sh.bak autogen.sh
+	cd "$BUILDDIR"
+	mkdir -p libmtp
+	cd libmtp
+	"$BASEDIR"/libmtp/configure \
+		CC="$MXEBUILDTYPE"-gcc \
+		--host="$MXEBUILDTYPE" \
+		--enable-shared \
+		--prefix="$BASEDIR"/"$MXEDIR"/usr/"$MXEBUILDTYPE"
+	make $JOBS
+	make install
+fi
+
 cd "$BUILDDIR"
 CURRENT_SHA=$(cd "$BASEDIR"/subsurface/libdivecomputer ; git describe)
 PREVIOUS_SHA=$(cat "libdivecomputer.SHA" 2>/dev/null || echo)