samples/bpf: Fix HDR_PROBE "echo"

echo should be replaced with echo -e to handle '\n' correctly, but
instead, replace it with printf as some systems can't handle echo -e.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191011002808.28206-2-ivan.khoronzhuk@linaro.org

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index a11d7270583d0f5861e944e26efa12d2b09ab92c..4f61725b1d86610db147c64d65104727ff11a090 100644 (file)
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -201,7 +201,7 @@ endif
 
 # Don't evaluate probes and warnings if we need to run make recursively
 ifneq ($(src),)
-HDR_PROBE := $(shell echo "\#include <linux/types.h>\n struct list_head { int a; }; int main() { return 0; }" | \
+HDR_PROBE := $(shell printf "\#include <linux/types.h>\n struct list_head { int a; }; int main() { return 0; }" | \
        $(HOSTCC) $(KBUILD_HOSTCFLAGS) -x c - -o /dev/null 2>/dev/null && \
        echo okay)