Use printf instead of echo -e in Makefile.configure

echo -e is not POSIX-compliant, but printf is supposed to interpret
escaped sequences like \n.

Fixes: #34
Signed-off-by: Thiago Macieira <thiago.macieira@intel.com>

Makefile.configure

@@ -22,7 +22,7 @@ configure: $(foreach it,$(ALLTESTS),check-$(it))
 
 check-%:
 	@echo $(subst check-,,$@)-tested := 1 $(OUT)
-	$(if $(V),,@)if echo -e "$($(subst check-,PROGRAM-,$@))" | \
+	$(if $(V),,@)if printf "$($(subst check-,PROGRAM-,$@))" | \
 	    $(CC) -xc $($(subst check-,CCFLAGS-,$@)) -o /dev/null - $(if $(V),,>/dev/null 2>&1); \
 	then \
 	    echo $(subst check-,,$@)-pass := 1 $(OUT); \