scripts/Kbuild.include: Fix portability problem of "echo -e"

"echo -e" is a GNU extension. When cross-compiling the kernel on a
BSD-like operating system (Mac OS X in my case), this doesn't work.

One could install a GNU version of echo, put that in the $PATH before
the system echo and use "/usr/bin/env echo", but the solution with
printf is simpler.

Since it is no disadvantage on Linux, I hope that gets accepted even if
cross-compiling the Linux kernel on another Unix operating system is
quite a rare use case.
Signed-off-by: Bernhard Walle <bernhard@bwalle.de>
Andreas Bießmann <andreas@biessmann.de>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/Kbuild.include

@@ -104,7 +104,7 @@ as-option = $(call try-run,\
 # Usage: cflags-y += $(call as-instr,instr,option1,option2)
 
 as-instr = $(call try-run,\
-	/bin/echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
+	printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
 
 # cc-option
 # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)