Make "make" bail out on first failure so that it's easier to spot!

Signed-off-by: Alex Zeffertt <alex.zeffertt@eu.citrix.com>

diff -r 45ec73c60222 Makefile
--- a/Makefile	Tue Mar 24 15:08:15 2009 +0000
+++ b/Makefile	Wed Mar 25 13:03:27 2009 +0000
@@ -6,7 +6,7 @@
 SUBDIRS	= libs common xenstored 
 
 bins:
-	@for dir in $(SUBDIRS); do \
+	@set -e ; for dir in $(SUBDIRS); do \
 		$(MAKE) -C $$dir; \
 	done
 
diff -r 45ec73c60222 libs/Makefile
--- a/libs/Makefile	Tue Mar 24 15:08:15 2009 +0000
+++ b/libs/Makefile	Wed Mar 25 13:03:27 2009 +0000
@@ -2,7 +2,7 @@
 
 .PHONY: all
 all: 
-	@for dir in $(SUBDIRS); do \
+	@set -e ; for dir in $(SUBDIRS); do \
 		$(MAKE) -C $$dir; \
 	done