add BUILD_DIR to OS builds

Makefile

@@ -20,18 +20,17 @@ help:
 build: clean $(OS_BUILDS) # Builds all binaries to BUILD_DIR/{linux,darwin,windows}
 
 dist: clean $(OS_BUILDS) archive checksum # Builds all binaries, archives with LIC_FILE, and creates sha256sum 
-
 
 linux: # Builds binary and outputs to BUILD_DIR/linux
-	@GOOS=linux CGO_ENABLED=0 go build -ldflags=$(GO_LDFLAGS) -o build/linux/$(APP)
+	@GOOS=linux CGO_ENABLED=0 go build -ldflags=$(GO_LDFLAGS) -o $(BUILD_DIR)/linux/$(APP)
 	@echo "output build/linux/$(APP)"
 
 darwin: # Builds binary and outputs to BUILD_DIR/darwin
-	@GOOS=darwin go build -ldflags=$(GO_LDFLAGS) -o build/darwin/$(APP)
+	@GOOS=darwin go build -ldflags=$(GO_LDFLAGS) -o $(BUILD_DIR)/darwin/$(APP)
 	@echo "output build/darwin/$(APP)"
 
 windows: # Builds binary and outputs to BUILD_DIR/windows
-	@GOOS=windows go build -ldflags=$(GO_LDFLAGS) -o build/windows/$(APP).exe
+	@GOOS=windows go build -ldflags=$(GO_LDFLAGS) -o $(BUILD_DIR)/windows/$(APP).exe
 	@echo "output build/windows/$(APP).exe"
 
 archive: # Create archives for distribution