Makefile: Do not create empty autoconf.mk on error

The build rules of
  - include/autoconf.mk.dep
  - include/autoconf.mk
  - include/spl-autoconf.mk
  - include/tpl-autoconf.mk
were not nice.

They created empty files (which are never updated)
if an error occurs during preprocessing.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

Makefile

@@ -638,36 +638,33 @@ checkdtc:
 # to regenerate the autoconf.mk file.
 $(obj)include/autoconf.mk.dep: $(obj)include/config.h include/common.h
 	@$(XECHO) Generating $@ ; \
-	set -e ; \
 	: Generate the dependancies ; \
 	$(CC) -x c -DDO_DEPS_ONLY -M $(CFLAGS) $(CPPFLAGS) \
-		-MQ $(obj)include/autoconf.mk include/common.h > $@
+		-MQ $(obj)include/autoconf.mk include/common.h > $@ || \
+		rm $@
 
 $(obj)include/autoconf.mk: $(obj)include/config.h
 	@$(XECHO) Generating $@ ; \
-	set -e ; \
 	: Extract the config macros ; \
-	$(CPP) $(CFLAGS) -DDO_DEPS_ONLY -dM include/common.h | \
-		sed -n -f tools/scripts/define2mk.sed > $@.tmp && \
-	mv $@.tmp $@
+	$(CPP) $(CFLAGS) -DDO_DEPS_ONLY -dM include/common.h > $@.tmp && \
+		sed -n -f tools/scripts/define2mk.sed $@.tmp > $@; \
+	rm $@.tmp
 
 # Auto-generate the spl-autoconf.mk file (which is included by all makefiles for SPL)
 $(obj)include/tpl-autoconf.mk: $(obj)include/config.h
 	@$(XECHO) Generating $@ ; \
-	set -e ; \
 	: Extract the config macros ; \
 	$(CPP) $(CFLAGS) -DCONFIG_TPL_BUILD  -DCONFIG_SPL_BUILD\
-			-DDO_DEPS_ONLY -dM include/common.h | \
-	sed -n -f tools/scripts/define2mk.sed > $@.tmp && \
-	mv $@.tmp $@
+			-DDO_DEPS_ONLY -dM include/common.h > $@.tmp && \
+		sed -n -f tools/scripts/define2mk.sed $@.tmp > $@; \
+	rm $@.tmp
 
 $(obj)include/spl-autoconf.mk: $(obj)include/config.h
 	@$(XECHO) Generating $@ ; \
-	set -e ; \
 	: Extract the config macros ; \
-	$(CPP) $(CFLAGS) -DCONFIG_SPL_BUILD -DDO_DEPS_ONLY -dM include/common.h | \
-	sed -n -f tools/scripts/define2mk.sed > $@.tmp && \
-	mv $@.tmp $@
+	$(CPP) $(CFLAGS) -DCONFIG_SPL_BUILD -DDO_DEPS_ONLY -dM include/common.h > $@.tmp && \
+		sed -n -f tools/scripts/define2mk.sed $@.tmp > $@; \
+	rm $@.tmp
 
 $(obj)include/generated/generic-asm-offsets.h:	$(obj)include/autoconf.mk.dep \
 	$(obj)include/spl-autoconf.mk \