suppress output of which
diff --git a/Makefile b/Makefile
index ddae1ce..f6821ec 100644
--- a/Makefile
+++ b/Makefile
@@ -257,7 +257,7 @@
 HAS_SYSTEM_PROTOBUF = false
 endif
 
-HAS_PROTOC = $(shell $(PROTOC_CMD) && echo true || echo false)
+HAS_PROTOC = $(shell $(PROTOC_CMD) > /dev/null && echo true || echo false)
 ifeq ($(HAS_PROTOC),true)
 HAS_VALID_PROTOC = $(shell $(PROTOC_CHECK_CMD) 2> /dev/null && echo true || echo false)
 else