morris AUR build error

g++ -DHAVE_CONFIG_H -I. -I..  -DLOCALEDIR=\"/usr/share/locale\" -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -I/usr/include/gtk-2.0 -I/usr/lib/gtk-2.0/include -I/usr/include/pango-1.0 -I/usr/include/harfbuzz -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/fribidi -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/atk-1.0 -pthread  -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -I/usr/include/dbus-1.0 -I/usr/lib/dbus-1.0/include -pthread -I/usr/include/libmount -I/usr/include/blkid  -I/usr/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -I/usr/include/dbus-1.0 -I/usr/lib/dbus-1.0/include -pthread -I/usr/include/libmount -I/usr/include/blkid  -D_FORTIFY_SOURCE=2  -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -fno-plt -MT control.o -MD -MP -MF .deps/control.Tpo -c -o control.o control.cc
In file included from control.cc:19:
control.hh:24:10: fatal error: boost/signals.hpp: No such file or directory
   24 | #include <boost/signals.hpp>
      |          ^~~~~~~~~~~~~~~~~~~
compilation terminated.
make[2]: *** [Makefile:370: control.o] Error 1
make[2]: *** Waiting for unfinished jobs....
In file included from boardgui.hh:24,
                 from appgui.hh:23,
                 from gtk_appgui_interface.hh:23,
                 from gtk_appgui.hh:22,
                 from morris.cc:20:
control.hh:24:10: fatal error: boost/signals.hpp: No such file or directory
   24 | #include <boost/signals.hpp>
      |          ^~~~~~~~~~~~~~~~~~~
compilation terminated.
make[2]: *** [Makefile:370: morris.o] Error 1
mv -f .deps/board.Tpo .deps/board.Po
make[2]: Leaving directory '/home/photon/.cache/yay/morris/src/morris-0.2/src'
make[1]: *** [Makefile:387: all-recursive] Error 1
make[1]: Leaving directory '/home/photon/.cache/yay/morris/src/morris-0.2'
make: *** [Makefile:285: all] Error 2
==> ERROR: A failure occurred in build().