update makefile to procude static build

Author: zaibon

Makefile

@@ -1,12 +1,14 @@
 all: client server
 
+BUILD_FLAGS = -ldflags '-extldflags "-fno-PIC -static"' -buildmode pie -tags 'osusergo netgo static_build'
+
 server:
 	mkdir -p bin
-	cd cmds/server && go build && mv server ../../bin/trs
+	cd cmds/server && go build $(BUILD_FLAGS) -o ../../bin/trs
 
 client:
 	mkdir -p bin
-	cd cmds/client && go build && mv client ../../bin/trc
+	cd cmds/client && go build $(BUILD_FLAGS) -o ../../bin/trc
 
 runserver: server
 	sudo bin/trs -config router.toml