3 files changed, 15 insertions, 13 deletions
diff --git a/.hgignore b/.hgignore
index 965992d787..e9c08742e7 100644
--- a/.hgignore
+++ b/.hgignore
@@ -11,6 +11,7 @@
 .*\.tar\.bz2$
 .*\.tar\.gz$
 .*~$
+.*\.tmp$
 .*\.flc$
 .*\.orig$
 .*\.rej$
diff --git a/Config.mk b/Config.mk
index f80732a618..33a2635249 100644
--- a/Config.mk
+++ b/Config.mk
@@ -120,16 +120,17 @@ buildmakevars2file = $(eval $(call buildmakevars2file-closure,$(1)))
 define buildmakevars2file-closure
     .PHONY: genpath
     genpath:
-	rm -f $(1);                                                    \
-	echo "SBINDIR=\"$(SBINDIR)\"" >> $(1);                         \
-	echo "BINDIR=\"$(BINDIR)\"" >> $(1);                           \
-	echo "LIBEXEC=\"$(LIBEXEC)\"" >> $(1);                         \
-	echo "LIBDIR=\"$(LIBDIR)\"" >> $(1);                           \
-	echo "SHAREDIR=\"$(SHAREDIR)\"" >> $(1);                       \
-	echo "PRIVATE_BINDIR=\"$(PRIVATE_BINDIR)\"" >> $(1);           \
-	echo "XENFIRMWAREDIR=\"$(XENFIRMWAREDIR)\"" >> $(1);           \
-	echo "XEN_CONFIG_DIR=\"$(XEN_CONFIG_DIR)\"" >> $(1);           \
-	echo "XEN_SCRIPT_DIR=\"$(XEN_SCRIPT_DIR)\"" >> $(1)
+	rm -f $(1).tmp;                                                    \
+	echo "SBINDIR=\"$(SBINDIR)\"" >> $(1).tmp;                         \
+	echo "BINDIR=\"$(BINDIR)\"" >> $(1).tmp;                           \
+	echo "LIBEXEC=\"$(LIBEXEC)\"" >> $(1).tmp;                         \
+	echo "LIBDIR=\"$(LIBDIR)\"" >> $(1).tmp;                           \
+	echo "SHAREDIR=\"$(SHAREDIR)\"" >> $(1).tmp;                       \
+	echo "PRIVATE_BINDIR=\"$(PRIVATE_BINDIR)\"" >> $(1).tmp;           \
+	echo "XENFIRMWAREDIR=\"$(XENFIRMWAREDIR)\"" >> $(1).tmp;           \
+	echo "XEN_CONFIG_DIR=\"$(XEN_CONFIG_DIR)\"" >> $(1).tmp;           \
+	echo "XEN_SCRIPT_DIR=\"$(XEN_SCRIPT_DIR)\"" >> $(1).tmp;           \
+	if ! cmp $(1).tmp $(1); then mv -f $(1).tmp $(1); fi
 endef
 
 ifeq ($(debug),y)
diff --git a/tools/libxl/Makefile b/tools/libxl/Makefile
index 9f74d4b284..d0be502e1d 100644
--- a/tools/libxl/Makefile
+++ b/tools/libxl/Makefile
@@ -52,12 +52,12 @@ $(LIBXLU_OBJS): $(AUTOINCS)
 	@rm -f $*.[ch]
 	$(FLEX) --header-file=$*.h --outfile=$*.c $<
 
-genpath-target = $(call buildmakevars2file,_libxl_paths.h)
+genpath-target = $(call buildmakevars2file,_libxl_paths.h.tmp)
 $(eval $(genpath-target))
 
 _libxl_paths.h: genpath
-	sed -e "s/\([^=]*\)=\(.*\)/#define \1 \2/g" $@ >_$@
-	mv _$@ $@
+	sed -e "s/\([^=]*\)=\(.*\)/#define \1 \2/g" $@.tmp >$@.2.tmp
+	if ! cmp $@.2.tmp $@; then mv -f $@.2.tmp $@; fi
 
 libxl_paths.c: _libxl_paths.h