feat: add install target to makefile

Makefile

@@ -22,6 +22,7 @@ bins?= \
 	81-deadlock
 
 bins_target=$(addprefix ${build_dir}/,${bins})
+install_bins_targets=$(addprefix ${install_dir}/bin/,${bins})
 
 src_dirs=$(sort $(dir $(wildcard ${src_dir}/**/)))
 includes=$(patsubst %,-I%,${src_dirs})
@@ -35,8 +36,12 @@ objs+=$(patsubst %.c,${build_dir}/%.o,${srcs})
 all: build
 
 .PHONY: install
-install: build
-	true
+install: build ${install_bins_targets}
+
+.PHONY: ${install_bins_targets}
+${install_bins_targets}: ${install_dir}/bin/%: ${build_dir}/%
+	@mkdir -p $(dir $@)
+	install $^ $@
 
 .PHONY: graphs
 graphs: