[PATCH] perf build: Fix unescaped # in perf build-test

[James Clark <james.clark@arm.com>]

With the following bash and make versions:

  $ make --version
  GNU Make 4.2.1
  Built for aarch64-unknown-linux-gnu

  $ bash --version
  GNU bash, version 5.0.17(1)-release (aarch64-unknown-linux-gnu)

This error is encountered when running the build-test target:

  $ make -C tools/perf build-test
  tests/make:181: *** unterminated call to function 'shell': missing ')'.  Stop.
  make: *** [Makefile:103: build-test] Error 2

Fix it by escaping the # which was causing make to interpret the rest of
the line as a comment leaving the unclosed opening bracket.

Fixes: 56d5229471ee ("tools build: Pass libbpf feature only if libbpf 1.0+")
Signed-off-by: James Clark <james.clark@arm.com>
---
 tools/perf/tests/make | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/tests/make b/tools/perf/tests/make
index d75876126631..8dd3f8090352 100644
--- a/tools/perf/tests/make
+++ b/tools/perf/tests/make
@@ -178,7 +178,7 @@ run += make_install_prefix_slash
 # run += make_install_pdf
 run += make_minimal
 
-old_libbpf := $(shell echo "#include <bpf/libbpf.h>" | $(CC) -E -dM -x c -| egrep -q "define[[:space:]]+LIBBPF_MAJOR_VERSION[[:space:]]+0{1}")
+old_libbpf := $(shell echo '\#include <bpf/libbpf.h>' | $(CC) -E -dM -x c -| egrep -q "define[[:space:]]+LIBBPF_MAJOR_VERSION[[:space:]]+0{1}")
 
 ifneq ($(old_libbpf),)
 run += make_libbpf_dynamic
-- 
2.34.1