add "all" target

Makefile

@@ -9,6 +9,7 @@ PKGS = wlroots wayland-server xcb xkbcommon libinput
 CFLAGS += $(foreach p,$(PKGS),$(shell pkg-config --cflags $(p)))
 LDLIBS += $(foreach p,$(PKGS),$(shell pkg-config --libs $(p)))
 
+all: dwl
 
 # wayland-scanner is a tool which generates C headers and rigging for Wayland
 # protocols, which are specified in XML. wlroots requires you to rig these up