include/bpf.mk: fix typo in clang version check

Signed-off-by: Felix Fietkau <[email protected]>

include/bpf.mk

@@ -64,7 +64,7 @@ BPF_CFLAGS := \
 	-O2 -emit-llvm -Xclang -disable-llvm-passes
 
 ifeq ($(DUMP),)
-  CLANG_VER:=$(shell clang -dM -E - < /dev/null | grep __clang_major__ | cut -d' ' -f3)
+  CLANG_VER:=$(shell $(CLANG) -dM -E - < /dev/null | grep __clang_major__ | cut -d' ' -f3)
   CLANG_VER_VALID:=$(shell [ "$(CLANG_VER)" -ge "$(CLANG_MIN_VER)" ] && echo 1 )
   ifeq ($(CLANG_VER_VALID),)
     $(error ERROR: LLVM/clang version too old. Minimum required: $(CLANG_MIN_VER), found: $(CLANG_VER))