Fix old libmtp detection on Ubuntu systems that don't support echo -e.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@20039 a1c6a512-1295-4272-9138-f99709370657
diff --git a/utils/MTP/Makefile b/utils/MTP/Makefile
index 8439f8b..9566a19 100644
--- a/utils/MTP/Makefile
+++ b/utils/MTP/Makefile
@@ -1,8 +1,8 @@
CFLAGS = -Wall
LIBS = -lmtp
OUTPUT = sendfirm
-EXTRA_CFLAGS = $(shell echo -e \
- '\#include <libmtp.h>\nlibmtp version: LIBMTP_VERSION' | \
+EXTRA_CFLAGS = $(shell printf \
+ '\#include <libmtp.h>\nlibmtp version: LIBMTP_VERSION\n' | \
gcc -E -P - -o - | grep -q '^libmtp version: 0\.2' && echo '-DOLDMTP')
all: $(OUTPUT)