From: Jean-Philippe Brucker <jean-philippe@linaro.org>
Date: Tue, 10 Nov 2020 17:43:11 +0100
Subject: tools/bpftool: Fix build slowdown
Patch-mainline: v5.11-rc1
Git-commit: 0639e5e97ad9c58dd15dcf6f6ccf677cfba39f98
References: bsc#1177028

Commit ba2fd563b740 ("tools/bpftool: Support passing BPFTOOL_VERSION to
make") changed BPFTOOL_VERSION to a recursively expanded variable,
forcing it to be recomputed on every expansion of CFLAGS and
dramatically slowing down the bpftool build. Restore BPFTOOL_VERSION as
a simply expanded variable, guarded by an ifeq().

Fixes: ba2fd563b740 ("tools/bpftool: Support passing BPFTOOL_VERSION to make")
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201110164310.2600671-8-jean-philippe@linaro.org
Acked-by: Gary Lin <glin@suse.com>
---
 tools/bpf/bpftool/Makefile |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -25,7 +25,9 @@ endif
 
 LIBBPF = $(LIBBPF_PATH)libbpf.a
 
-BPFTOOL_VERSION ?= $(shell make -rR --no-print-directory -sC ../../.. kernelversion)
+ifeq ($(BPFTOOL_VERSION),)
+BPFTOOL_VERSION := $(shell make -rR --no-print-directory -sC ../../.. kernelversion)
+endif
 
 $(LIBBPF): FORCE
 	$(if $(LIBBPF_OUTPUT),@mkdir -p $(LIBBPF_OUTPUT))