diff --git a/programs/bpf/c/sdk/bpf.mk b/programs/bpf/c/sdk/bpf.mk
index 5d1491dbd9..a39cc1a04d 100644
--- a/programs/bpf/c/sdk/bpf.mk
+++ b/programs/bpf/c/sdk/bpf.mk
@@ -10,7 +10,7 @@ INC_DIRS ?=
 SRC_DIR ?= ./src
 OUT_DIR ?= ./out
 
-OS=$(uname)
+OS=$(shell uname)
 ifeq ($(OS),Darwin)
 LLVM_DIR ?= $(brew --prefix llvm)
 endif